TMP400AIDBQR

TMP400 TI | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 25

Technical content

/C0066/C0117/C0114/C0114/C0262/C0066/C0114/C0111/C0119/C0110 /C0080/C0114/C0111/C0100/C0117/C0099/C0116/C0115 /C0102/C0114/C0111/C0109 /C0084/C0101/C0120/C0097/C0115 /C0073/C0110/C0115/C0116/C0114/C0117/C0109/C0101/C0110/C0116/C0115

FEATURES

DESCRIPTION

APPLICATIONS

Device□ID□Register Manufacturer□ID□Register Consecutive□Alert Configuration□Register TR TL Status□Register Conversion□Rate Register N-Factor Correction 7,□8 Bus□Interface Pointer□Register Resolution□Register Configuration□Register Local□T emp□Low□Limit Local□T emp□High□Limit Remote□T emp□Low□Limit Remote□T emp□High□Limit Remote T emperature Register Local T emperature Register T emperature Comparators Interrupt Configuration SCL GND

11 ALERT

Remote□T emperature□Min/Max□Register Local□T emperature□Min/Max□Register STBY A1 A0 6 10 TMP400 SBOS404 DECEMBER 2007 C Remote and Local TEMPERATURE SENSOR with N-Factor and Series Resistance Correction C REMOTE DIODE SENSOR The TMP400 is a remote temperature sensor monitor with a built-in local temperature sensor. The remote C LOCAL TEMPERATURE SENSOR temperature sensor diode-connected transistors are PROGRAMMABLE NON-IDEALITY FACTOR typically low-cost, NPN- or PNP-type transistors or PROGRAMMABLE SERIES RESISTANCE diodes that are an integral part of microcontrollers, CANCELLATION microprocessors, or FPGAs. ALERT FUNCTION Remote accuracy is C for multiple IC PROGRAMMABLE RESOLUTION: to Bits manufacturers, with no calibration needed. The Two-Wire serial interface accepts SMBus write byte, PROGRAMMABLE THRESHOLD LIMITS read byte, send byte, and receive byte commands to TWO-WIRE/ SMBus SERIAL INTERFACE program the alarm thresholds and to read MINIMUM AND MAXIMUM TEMPERATURE temperature data. MONITORS The TMP400 is customizable with programmable: MULTIPLE INTERFACE ADDRESSES series resistance cancellation, non-ideality factor, ALERT PIN CONFIGURATION resolution, and threshold limits. Other are: minimum and maximum temperature monitors, wide DIODE FAULT DETECTION remote temperature measurement range (up to +127.9375 C), diode fault detection, and temperature alert function. LCD/ DLP /LCOS PROJECTORS The TMP400 is available in a QSSOP-16 package. SERVERS INDUSTRIAL CONTROLLERS CENTRAL OFFICE TELECOM EQUIPMENT DESKTOP AND NOTEBOOK COMPUTERS STORAGE AREA NETWORKS (SAN) INDUSTRIAL AND MEDICAL EQUIPMENT PROCESSOR/FPGA TEMPERATURE MONITORING Please be aware that an important notice concerning availability, standard warranty, and use in critical sheet. DLP is a registered trademark of Texas Instruments. SMBus is a trademark of Intel Corp. All other trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Copyright 2007, Texas Instruments Incorporated Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.

www.ti.com ABSOLUTE MAXIMUM RATINGS (1) PIN CONFIGURATION NC STBY SCL NC SDA ALERT NC NC D/c45 NC GND GND TMP400 TMP400 SBOS404 DECEMBER 2007 This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. ORDERING INFORMATION (1) PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR PACKAGE MARKING TMP400 QSSOP-16 DBQ TMP400 (1) For the most current package and ordering information see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com TMP400 UNIT Power Supply, V S V Input Voltage, pins 10, and only 0.5 to V S 0.5 V Input Voltage, pins 11, 12, and only 0.5 to V Input Current mA Operating Temperature Range to +127 C Storage Temperature Range to +130 C Junction Temperature J max) +150 C Human Body Model (HBM) 3000 V ESD Rating Charged Device Model (CDM) 1000 V Machine Model (MM) 200 V (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not supported. TERMINAL FUNCTIONS PIN NAME 13, Positive supply (2.7V to 5.5V) Positive connection to remote temperature sensor Negative connection to remote temperature D sensor Address pin GND Ground Address pin Alert, active low, open-drain; requires pull-up ALERT resistor to Serial data line for SMBus, open-drain; SDA requires pull-up resistor to Serial clock line for SMBus, open-drain; SCL requires pull-up resistor to STBY Standby pin Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com ELECTRICAL CHARACTERISTICS TMP400 SBOS404 DECEMBER 2007 At T A C to +125 C and V S 2.7V to 5.5V, unless otherwise noted. TMP400 PARAMETER CONDITIONS MIN TYP MAX UNIT TEMPERATURE ERROR Local Temperature Sensor TE LOCAL T A C to +125 C 1.25 2.5 C V S 3.3V, T A +15 C to +85 C 0.0625 C Remote Temperature Sensor (1) (2) TE REMOTE V S 3.3V, T A +15 C to +75 T D C to +125 C (3) 0.0625 C V S 3.3V, T A C to +100 T D C to +125 C (3) C T A C to +125 T D C to +125 C (3) C vs Supply Local/Remote V S 2.7V to 5.5V 0.2 0.5 C/V TEMPERATURE MEASUREMENT Conversion Time (per channel) (4) 105 115 125 ms Resolution Local Temperature Sensor (programmable) Bits Remote Temperature Sensor Bits Remote Sensor Source Currents High Series Resistance Ω Maximum 120 µ A Medium High µ A Medium Low µ A Low µ A Remote Transistor Ideality Factor η TMP400 Optimized Ideality Factor 1.008 SMBus INTERFACE Logic Input High Voltage (SCL, SDA) V IH 2.1 V Logic Input Low Voltage (SCL, SDA) V IL 0.8 V Hysteresis 500 mV SMBus Output Low Sink Current mA Logic Input Current µ A SMBus Input Capacitance (SCL, SDA) pF SMBus Clock Frequency 3.4 MHz SMBus Timeout ms SCL Falling Edge to SDA Valid Time µ s DIGITAL OUTPUTS Output Low Voltage V OL I OUT 6mA 0.15 0.4 V High-Level Output Leakage Current I OH V OUT V S 0.1 µ A ALERT Output Low Sink Current ALERT Forced to 0.4V mA POWER SUPPLY Specified Voltage Range V S 2.7 5.5 V Quiescent Current I Q 0.0625 Conversions per Second µ A Eight Conversions per Second 420 525 µ A Serial Bus Inactive, Shutdown Mode µ A Serial Bus Active, f S 400kHz, Shutdown Mode µ A Serial Bus Active, f S 3.4MHz, Shutdown Mode 350 µ A Undervoltage Lock Out 2.3 2.4 2.6 V Power-On Reset Threshold POR 1.6 2.3 V TEMPERATURE RANGE Specified Range +125 C Storage Range +130 C Thermal Resistance, QSSOP C/W (1) Tested with less than Ω effective series resistance and 100pF differential input capacitance. (2) RC '1'. (3) T D is the remote temperature measured at the diode. (4) RES1 '1' and RES0 '1' for 12-bit resolution. Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com TYPICAL CHARACTERISTICS /c45 1 /c45 2 /c45 3 Ambient□T emperature,□T ( C)/c176 A /c45 50 /c45 25 1251007550250 Remote□T emperature□Error□( C) /c176 V =□3.3VS T =□+25 CREMOTE /c176 30□T ypical□Units□Shown /c104 =□1.008 RC□=□1 Local□T emperature□Error□( /c176C Ambient□T emperature,□T (A /c176 C) 3.0 2.0 1.0 /c45 1.0 /c45 2.0 /c45 3.0 /c45 50 125/c45 25 0 25 50 75 100 50□Units□ShownV =□3.3VS /c45 20 /c45 40 /c45 60 Leakage□Resistance□(M )/c87 0 5 10 15 20 25 Remote□T emperature□Error□( C)/c176 R GND/c45 R V S/c45 Remote□T emperature□Error□( /c176C R /c87( )S 2.0 1.5 1.0 0.5 /c45 0.5 /c45 1.0 /c45 1.5 /c45 2.0 0 3000500 1000 1500 2000 2500 V =□2.7VS V =□5.5VS RC□=□1 /c45 1 /c45 2 /c45 3 Capacitance□(nF) Remote□T emperature□Error□( C) /c176 Remote□T emperature□Error□( /c176C R ( /c87 )S 2.0 1.5 1.0 0.5 /c45 0.5 /c45 1.0 /c45 1.5 /c45 2.0 0 3000500 1000 1500 2000 2500 V =□2.7VS V =□5.5VS RC□=□1 TMP400 SBOS404 DECEMBER 2007 At T A +25 C and V S 5.0V, unless otherwise noted. REMOTE TEMPERATURE ERROR LOCAL TEMPERATURE ERROR vs TEMPERATURE vs TEMPERATURE Figure Figure REMOTE TEMPERATURE ERROR REMOTE TEMPERATURE ERROR vs SERIES RESISTANCE vs LEAKAGE RESISTANCE (Diode-Connected Transistor, 2N3906 PNP) Figure Figure REMOTE TEMPERATURE ERROR vs SERIES RESISTANCE REMOTE TEMPERATURE ERROR (GND Collector-Connected Transistor, 2N3906 PNP) vs DIFFERENTIAL CAPACITANCE Figure Figure Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com /c45 5 /c45 10 /c45 15 /c45 20 /c45 25 Frequency□(MHz) 0 5 10 15 T emperature□Error□( C) /c176 Local□100mV NoisePP Remote□100mV NoisePP Local□250mV NoisePP Remote□250mV NoisePP 500 450 400 350 300 250 200 150 100 Conversion□Rate□(conversions/sec) 0.0625 0.125 0.25 0.5 1 2 4 8 I ( A)/c109 Q V =□2.7VS V =□5.5VS 500 450 400 350 300 250 200 150 100 SCL□Clock□Frequency□(Hz) 1k 10k 100k 1M 10M I ( A) /c109 Q V =□3.3VS V =□5.5VS I ) Q /c109A V (S V) TMP400 SBOS404 DECEMBER 2007 TYPICAL CHARACTERISTICS (continued) At T A +25 C and V S 5.0V, unless otherwise noted. TEMPERATURE ERROR QUIESCENT CURRENT vs POWER-SUPPLY NOISE FREQUENCY vs CONVERSION RATE Figure Figure SHUTDOWN QUIESCENT CURRENT SHUTDOWN QUIESCENT CURRENT vs SCL CLOCK FREQUENCY vs SUPPLY VOLTAGE Figure Figure 10. Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com APPLICATION INFORMATION SERIES RESISTANCE CANCELLATION 0.1/c109 F 10k/c87 (typ) 10k/c87 (typ) 10k/c87 (typ) TMP400 D/c45 7,□8 R (2) S R (2) S C (3) DIFF C (3) DIFF R (2) S R (2) S GND SCL SDA ALERT +5V T wo-Wire□Bus/ SMBus Controller Diode-connected□configuration : (1) Series□Resistance Transistor-connected□configuration :(1) STBY TMP400 SBOS404 DECEMBER 2007 other devices if desired for a wired-OR The TMP400 is a dual-channel digital temperature implementation. A 0.1 µ F power-supply bypass sensor that combines a local die temperature capacitor is recommended for good local bypassing. measurement channel and a remote junction Figure shows a typical configuration for the temperature measurement channel in a QSSOP-16 TMP400. package. The TMP400 is Two-Wire and SMBus interface-compatible, and is specified over a temperature range of C to +125 The TMP400 contains multiple registers for holding configuration Series resistance in an application circuit that typically information, temperature measurement results, results from printed circuit board (PCB) trace temperature comparator maximum/minimum limits, resistance and remote line length (see Figure can and status information. be automatically programmed to be cancelled by the TMP400 by setting the RC bit to '1' in the Resolution User-programmed high and low temperature limits Register, preventing what would otherwise result in a stored in the TMP400 can be used to monitor local temperature offset. and remote temperatures to trigger an over/under temperature alarm ALERT A total of up to Ω of series line resistance is cancelled by the TMP400 if the RC bit is enabled, The TMP400 requires only a transistor connected eliminating the need for additional characterization between and D for proper remote temperature and temperature offset correction. Upon power-up, sensing operation. The SCL and SDA interface pins the RC bit is disabled (RC 0). require pull-up resistors as part of the communication bus, while ALERT is an open-drain output that also See the two Remote Temperature Error vs Series needs a pull up resistor. ALERT may be shared with Resistance typical characteristics curves Figure and Figure for details on the effect of series resistance and power-supply voltage on sensed remote temperature error. (1) Diode-connected configuration provides better settling time. Transistor-connected configuration provides better series resistance cancellation. (2) R S should be less than 1.5k Ω in most applications. (3) C DIFF should be less than 1000pF in most applications. Figure 11. Basic Connections Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com DIFFERENTIAL INPUT CAPACITANCE REGISTER INFORMATION TEMPERATURE MEASUREMENT DATA POINTER REGISTER Resolution□Register Configuration□Register Status□Register Identification□Registers Consecutive□Alert□Register Local□T emperature□Min/Max Conversion□Rate□Register Remote□T emperature□Min/Max Local□and□Remote□Limit□Registers Local□and□Remote□T emperature□Registers SDA SCL Pointer□Register I/O Control Interface TMP400 SBOS404 DECEMBER 2007 byte stores the decimal fraction value of the temperature and allows a higher measurement The TMP400 tolerates differential input capacitance resolution. The measurement resolution for the of up to 1000pF if RC (if RC input remote channel is 0.0625 and is not adjustable. capacitance can be as high as 2200pF) with minimal The measurement resolution for the local channel is change in temperature error. The effect of adjustable; it can be set for 0.5 0.25 0.125 capacitance on sensed remote temperature error is or 0.0625 C by setting the RES1 and RES0 bits of illustrated in the typical characteristic curve, Remote the Resolution Register; see the Resolution Register Temperature Error vs Differential Capacitance section Table Figure The TMP400 contains multiple registers for holding Temperature measurement data are taken over a configuration information, temperature measurement default range of C to +127.9375 C for both local results, temperature comparator maximum/minimum, and remote locations. limits, and status information. These registers are described in Figure and Table Temperature data resulting from conversions within the default measurement range are represented in binary form, as shown in Table Binary column. Note that any temperature above +127.9375 C Figure shows the internal register structure of the results in a value of 127.9375 (7Fh/F0h). TMP400. The 8-bit Pointer Register is used to Temperatures below C results in a value of address a given data register. The Pointer Register (BF/00h). The TMP400 is specified only for ambient identifies which of the data registers should respond temperatures ranging from C to +125 to a read or write command on the Two-Wire bus. Parameters in the Absolute Maximum Ratings table This register is set with every write command. A write must be observed. command must be issued to set the proper value in the Pointer Register before executing a read Table Temperature Data Format command. Table describes the pointer address of REMOTE TEMPERATURE REGISTER the registers available in the TMP400. The power-on reset (POR) value of the Pointer Register is 00h DIGITAL OUTPUT (BINARY) (0000 0000b). TEMPERATURE HIGH BYTE LOW BYTE HEX 128 0111 1111 1111 0000 7F/F0 127.9375 0111 1111 1111 0000 7F/F0 100 0110 0100 0000 0000 0101 0000 0000 0000 0100 1011 0000 0000 4B/00 0011 0010 0000 0000 0001 1001 0000 0000 0.25 0000 0000 0100 0000 0000 0000 0000 0000 0.25 1111 1111 1100 0000 FF/C0 1110 0111 0000 0000 E7/00 1100 1001 0000 0000 C9/00 1011 1111 0000 0000 BF/00 Both local and remote temperature data use two Figure 12. Internal Register Structure bytes for data storage. The high byte stores the temperature with C resolution. The second (or low) Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com TMP400 SBOS404 DECEMBER 2007 Table Register Map POINTER ADDRESS (HEX) BIT DESCRIPTIONS POWER-ON READ WRITE RESET (HEX) REGISTER DESCRIPTIONS Local Temperature NA (1) LT11 LT10 LT9 LT8 LT7 LT6 LT5 LT4 (High Byte) Remote Temperature NA RT11 RT10 RT9 RT8 RT7 RT6 RT5 RT4 (High Byte) NA BUSY LHIGH LLOW RHIGH RLOW OPEN Status Register MASK1 SD Configuration Register Conversion Rate Register Local Temperature High LTH11 LTH10 LTH9 LTH8 LTH7 LTH6 LTH5 LTH4 Limit (High Byte) Local Temperature Low Limit LTL11 LTL10 LTL9 LTL8 LTL7 LTL6 LTL5 LTL4 (High Byte) Remote Temperature High RTH11 RTH10 RTH9 RTH8 RTH7 RTH6 RTH5 RTH4 Limit (High Byte) Remote Temperature Low RTL11 RTL10 RTL9 RTL8 RTL7 RTL6 RTL5 RTL4 Limit (High Byte) NA XX X (2) X X X X X X X One-Shot Start Remote Temperature NA RT3 RT2 RT1 RT0 (Low Byte) Remote Temperature High RTH3 RTH2 RTH1 RTH0 Limit (Low Byte) Remote Temperature Low RTL3 RTL2 RTL1 RTL0 Limit (Low Byte) Local Temperature NA LT3 LT2 LT1 LT0 (Low Byte) Local Temperature High LTH3 LTH2 LTH1 LTH0 Limit (Low Byte) Local Temperature Low Limit LTL3 LTL2 LTL1 LTL0 (Low Byte) NC7 NC6 NC5 NC4 NC3 NC2 NC1 NC0 N-factor Correction RC RES1 RES0 Resolution Register TO_EN Consecutive Alert Register Local Temperature Minimum LMT11 LMT10 LMT9 LMT8 LMT7 LMT6 LMT5 LMT4 (High Byte) Local Temperature Minimum LMT3 LMT2 LMT1 LMT0 (Low Byte) Local Temperature Maximum LXT11 LXT10 LXT9 LXT8 LXT7 LXT6 LXT5 LXT4 (High Byte) Local Temperature Maximum LXT3 LXT2 LXT1 LXT0 (Low Byte) Remote Temperature RMT11 RMT10 RMT9 RMT8 RMT7 RMT6 RMT5 RMT4 Minimum (High Byte) Remote Temperature RMT3 RMT2 RMT1 RMT0 Minimum (Low Byte) Remote Temperature RXT11 RXT10 RXT9 RXT8 RXT7 RXT6 RXT5 RXT4 Maximum (High Byte) Remote Temperature RXT3 RXT2 RXT1 RXT0 Maximum (Low Byte) NA FC FF X (2) X X X X X X X Software Reset FE NA Manufacturer ID FF NA Device ID (1) NA not applicable; register is write- or read-only. (2) X indeterminate state. Writing any value to this register indicates a software reset; see the Software Reset section. Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com TEMPERATURE REGISTERS LIMIT REGISTERS STATUS REGISTER TMP400 SBOS404 DECEMBER 2007 byte first) to pointer address 0Bh. The local temperature high limit is obtained by reading the high The TMP400 has four 8-bit registers that hold byte from pointer address 05h and the low byte from temperature measurement results. Both the local pointer address 16h. The power-on reset value of the channel and the remote channel have a high byte local temperature high limit is 7Fh/00h (+127 C). register that contains the most significant bits (MSBs) of the temperature analog-to-digital converter (ADC) Similarly, the local temperature low limit is set by result, and a low byte register that contains the least writing the high byte to pointer address 0Ch and significant bits (LSBs) of the temperature ADC result. writing the low byte to pointer address 17h, or by The local channel high byte address is 00h; the local using a single two-byte write command to pointer channel low byte address is 15h. The remote channel address 0Ch. The local temperature low limit is read high byte is at address 01h; the remote channel low by reading the high byte from pointer address 06h byte address is 10h. These read-only registers are and the low byte from pointer address 17h, or by updated by the ADC each time a temperature using a two-byte read from pointer address 06h. The measurement is completed. power-on reset value of the local temperature low limit register is C9h/00h C). The TMP400 contains circuitry to assure that a low byte register read command returns data from the The remote temperature high limit is set by writing the same ADC conversion as the immediately preceding high byte to pointer address 0Dh and writing the low high byte read command. This assurance remains byte to pointer address 13h, or by using a two-byte valid only until another register is read. For proper write command to pointer address 0Dh. The remote operation, the high byte of a temperature register temperature high limit is obtained by reading the high should be read first. The low byte register should be byte from pointer address 07h and the low byte from read in the next read command. The low byte register pointer address 13h, or by using a two-byte read may be left unread if the LSBs are not needed. command from pointer address 07h. The power-on Alternatively, the temperature registers may be read reset value of the Remote Temperature High Limit as a 16-bit register by using a single two-byte read Register is 7Fh/00h (+127 C). command from address 00h for the local channel The remote temperature low limit is set by writing the result or from address 01h for the remote channel high byte to pointer address 0Eh and writing the low result. The high byte is output first, followed by the byte to pointer address 14h, or by using a two-byte low byte. Both bytes of this read operation are from write to pointer address 0Eh. The remote temperature the same ADC conversion. The power-on reset value low limit is read by reading the high byte from pointer of both temperature registers is 00h. address 08h and the low byte from pointer address 14h, or by using a two-byte read from pointer address 08h. The power-on reset value of the Remote Temperature Low Limit Register is C9h/00h C). The TMP400 has eight registers for setting comparator limits for both the local and remote measurement channels. These registers have read and write capability. The High and Low Limit The TMP400 has a Status Register to report the state Registers for both channels span two registers, as do of the temperature comparators. Table shows the the temperature registers. The local temperature high Status Register bits. The Status Register is read-only limit is set by writing the high byte to pointer address and is read by reading from pointer address 02h. 0Bh and writing the low byte to pointer address 16h, or by using a single two-byte write command (high Table Status Register Format STATUS REGISTER (Read 02h, Write NA) BIT BIT NAME BUSY LHIGH LLOW RHIGH RLOW OPEN POR VALUE (1) (1) The BUSY bit will change to almost immediately 100 µ following power-up, as the TMP400 begins the first temperature conversion. It is high whenever the TMP400 converts a temperature reading. Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com CONFIGURATION REGISTER TMP400 SBOS404 DECEMBER 2007 The BUSY bit is if the ADC makes a conversion. It The TMP400 NORs LHIGH, LLOW, RHIGH, RLOW, is if the ADC is not converting. and OPEN, so a status change for any of these flags from to automatically causes the ALERT pin to The OPEN bit is if the remote transistor was go low. detected as open since the last read of the Status Register. The OPEN status is only detected when the ADC attempts to convert a remote temperature. The Configuration Register controls shutdown mode The LHIGH bit is if the local high limit was and disables the ALERT pin. The Configuration exceeded since the last clearing of the Status Register is set by writing to pointer address 09h and Register. The RHIGH bit is if the remote high limit read by reading from pointer address 03h. was exceeded since the last clearing of the Status Register. The MASK bit (bit enables or disables the ALERT pin output. If MASK is set to the ALERT pin goes The LLOW bit is if the local low limit was exceeded low when one of the temperature measurement since the last clearing of the Status Register. The channels exceeds its high or low limits for the chosen RLOW bit is if the remote low limit was exceeded number of consecutive conversions. If the MASK bit since the last clearing of the Status Register. is set to the TMP400 retains the ALERT pin The values of the LLOW, RLOW, and OPEN bits are status, but the ALERT pin does not go low. latched and read as until the Status Register is The shutdown (SD) bit (bit enables or disables the read or a device reset occurs. These bits are cleared temperature measurement circuitry. If SD the by reading the Status Register, provided that the TMP400 converts continuously at the rate set in the condition causing the flag to be set no longer exists. conversion rate register. When SD is set to the The BUSY bit is not latched and is not cleared by TMP400 immediately stops converting and enters a reading the Status Register. The BUSY bit always shutdown mode. When SD is set to again, the indicates the current state and updates appropriately TMP400 resumes continuous conversions. at the end of the corresponding ADC conversion. Clearing the Status Register bits does not clear the The remaining bits of the Configuration Register are state of the ALERT pin; an SMBus alert response reserved and must always be set to The power-on address command must be used to clear the ALERT reset value for this register is 00h. Table pin. summarizes the bits of the Configuration Register. Table Configuration Register Bit Descriptions CONFIGURATION REGISTER (Read 03h, Write 09h, POR 00h) BIT NAME FUNCTION POWER-ON RESET VALUE ALERT Enabled MASK ALERT Masked Run SD Shut Down Reserved Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com RESOLUTION REGISTER CONVERSION RATE REGISTER N-FACTOR CORRECTION REGISTER V V =/c45BE2 BE1 nkT q ln (1) ONE-SHOT (OS) n =eff 1.008 300/c180 (300 N )/c45 ADJUST (2) N =□300 /c45ADJUST 300 1.008/c180 neff (3) TMP400 SBOS404 DECEMBER 2007 conversion. This mode is useful to reduce power consumption in the TMP400 when continuous The RES1 and RES0 bits (resolution bits and temperature monitoring is not required. When the respectively) of the Resolution Register set the configuration register is read, the OS bit always reads resolution of the local temperature measurement '0' channel. Remote temperature measurement channel resolution is not affected. Changing the local channel resolution also affects the conversion time and rate of the TMP400. The Resolution Register is set by The Conversion Rate Register controls the rate at writing to pointer address 1Ah and is read by reading which temperature conversions are performed. This from pointer address 1Ah. Table shows the register adjusts the idle time between conversions but resolution bits for the Resolution Register. not the conversion timing itself, thereby allowing the TMP400 power dissipation to be balanced with the Table Resolution Register: Local Channel temperature register update rate. Table shows the Programmable Resolution conversion rate options and corresponding current consumption. By default, the TMP400 converts every RESOLUTION REGISTER four seconds. (Read 1Ah, Write 1Ah, POR 18h) CONVERSION RES1 RES0 RESOLUTION TIME (Typical) Bits (0.5 12.5ms The TMP400 allows for a different n -factor value to Bits (0.25 25ms be used for converting remote channel measurements to temperature. The remote channel Bits (0.125 50ms uses sequential current excitation to extract a Bits (0.0625 100ms differential V BE voltage measurement to determine the temperature of the remote transistor. Equation Bits and of the Resolution Register must always relates this voltage and temperature. be set to Bits through of the Resolution Register must always be set to The power-on reset value of this register is 18h. Resistance correction (RC) is not automatically enabled on power-on; see the Series Resistance Cancellation The value n in Equation is a characteristic of the section for information on RC. particular transistor used for the remote channel. The default value for the TMP400 is n 1.008. The value in the N-Factor Correction Register may be used to The TMP400 a One-Shot Temperature adjust the effective n -factor according to Equation Measurement Mode. When the device is in Shutdown and Equation Mode, writing a to the OS bit starts a single temperature conversion. The device returns to the shutdown state at the completion of the single Table Conversion Rate Register CONVERSION RATE REGISTER (Read 04h, Write 0Ah, POR 02h) AVERAGE I Q (TYP) µ CONVERSION/SEC V S 2.7V V S 5.5V 0.0625 0.125 0.25 0.5 103 128 155 190 220 07h to 0Fh 373 413 Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com MINIMUM AND MAXIMUM REGISTERS SOFTWARE RESET TMP400 SBOS404 DECEMBER 2007 The n -correction value must be stored in The Local Temperature Maximum Register may be two s-complement format, yielding an effective data read by reading the high byte from pointer address range from 128 to +127. The n -correction value may 32h and the low byte from pointer address 33h. The be written to and read from pointer address 18h. The Local Temperature Maximum Register may also be register power-on reset value is 00h; thus, the read by using a two-byte read command from pointer register has no effect unless written to. The n -factor address 32h. The Local Temperature Maximum range is shown in Table Register is reset at power-on by executing the chip reset command, or by writing any value to any of Table N-Factor Range pointer addresses 30h through 37h. The reset value for these registers is 80h/00h. N ADJUST The Remote Temperature Minimum Register may be BINARY HEX DECIMAL N read by reading the high byte from pointer address 01111111 127 1.747977 34h and the low byte from pointer address 35h. The 00001010 1.042759 Remote Temperature Minimum Register may also be 00001000 1.035616 read by using a two-byte read command from pointer 00000110 1.028571 address 34h. The Remote Temperature Minimum Register is reset at power-on by executing the chip 00000100 1.021622 reset command, or by writing any value to any of 00000010 1.014765 pointer addresses 30h through 37h. The reset value 00000001 1.011371 for these registers is 7Fh/F0h. 00000000 1.008 The Remote Temperature Maximum Register may be 11111111 FF 1.004651 read by reading the high byte from pointer address 11111110 FE 1.001325 36h and the low byte from pointer address 37h. The 11111100 FC 0.994737 Remote Temperature Maximum Register may also be 11111010 FA 0.988235 read by using a two-byte read command from pointer address 36h. The Remote Temperature Maximum 11111000 0.981818 Register is reset at power-on by executing the chip 11110110 0.975484 reset command, or by writing any value to any of 10000000 128 0.706542 pointer addresses 30h through 37h. The reset value for these registers is 80h/00h. The TMP400 stores the minimum and maximum temperatures measured since power-on, chip-reset, The TMP400 may be reset by writing any value to or minimum and maximum register reset for both the Pointer Register FCh. A reset restores the power-on local and remote channels. The Local Temperature reset state to all of the TMP400 registers as well as Minimum Register may be read by reading the high aborts any conversion in process and clears the byte from pointer address 30h and the low byte from ALERT pin. pointer address 31h. The Local Temperature The TMP400 also supports reset via the Two-Wire Minimum Register may also be read by using a general call address (00000000). The TMP400 two-byte read command from pointer address 30h. acknowledges the general call address and responds The Local Temperature Minimum Register is reset at to the second byte. If the second byte is 00000110, power-on, by executing the chip-reset command, or the TMP400 latches the status of the address pins by writing any value to any of pointer addresses 30h and executes a software reset. A 500 µ s time delay through 37h. The reset value for these registers is must be observed after a general-call command. The 7Fh/F0h. TMP400 takes no action in response to other values in the second byte. Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com CONSECUTIVE ALERT REGISTER SERIAL INTERFACE SERIAL BUS ADDRESS BUS OVERVIEW READ/WRITE OPERATIONS TMP400 SBOS404 DECEMBER 2007 The value in the Consecutive Alert Register (address The TMP400 operates only as a slave device on 22h) determines how many consecutive out-of-limit either the Two-Wire bus or the SMBus. Connections measurements must occur on a measurement to either bus are made via the open-drain I/O lines, channel before the ALERT signal is activated. The SDA, and SCL. The SDA and SCL pins feature value in this register does not affect bits in the Status integrated spike suppression filters and Schmitt Register. Values of one, two, three, or four triggers to minimize the effects of input spikes and consecutive conversions can be selected; one bus noise. The TMP400 supports the transmission conversion is the default. This function allows protocol for fast (1kHz to 400kHz) and high-speed additional filtering for the ALERT pin. The consecutive (1kHz to 3.4MHz) modes. All data bytes are alert bits are shown in Table transmitted MSB first. Table Consecutive Alert Register CONSECUTIVE ALERT REGISTER To communicate with the TMP400, the master must (READ 22h, WRITE 22h, POR 01h) first address slave devices via a slave address byte. NUMBER OF CONSECUTIVE The slave address byte consists of seven address OUT-OF-LIMIT bits, and a direction bit indicating the intent of MEASUREMENTS executing a read or write operation. The address of the TMP400 is set by the and pins. TMP400 addresses and corresponding and configurations are shown in Table Table Device Addresses (1) Note that bit of the Consecutive Alert Register controls the ADDRESS enable/disable of the timeout function. See the Timeout Function section for a feature. GND GND 0011 000 GND High-Z 0011 001 GND V CC 0011 010 The TMP400 is SMBus interface-compatible. In High-Z GND 0101 001 SMBus protocol, the device that initiates the transfer High-Z High-Z 0101 010 is called a master and the devices controlled by the High-Z V CC 0101 011 master are slaves The bus must be controlled by a V CC GND 1001 100 master device that generates the serial clock (SCL), controls the bus access, and generates the START V CC High-Z 1001 101 and STOP conditions. V CC V CC 1001 110 To address a specific device, a START condition is initiated. START is indicated by pulling the data line (SDA) from a high to low logic level while SCL is Accessing a particular register on the TMP400 is high. All slaves on the bus shift in the slave address accomplished by writing the appropriate value to the byte, with the last bit indicating whether a read or Pointer Register. The value for the Pointer Register is write operation is intended. During the ninth clock the first byte transferred after the slave address byte pulse, the slave being addressed responds to the with the W bit low. Every write operation to the master by generating an Acknowledge and pulling TMP400 requires a value for the Pointer Register SDA low. (see Figure Data transfer is then initiated and sent over eight When reading from the TMP400, the last value stored clock pulses followed by an Acknowledge bit. During in the Pointer Register by a write operation is used to data transfer, SDA must remain stable while SCL is determine which register is read by a read operation. high, because any change in SDA while SCL is high To change the register pointer for a read operation, a is interpreted as a control signal. new value must be written to the Pointer Register. Once all data have been transferred, the master This transaction is accomplished by issuing a slave generates a STOP condition. STOP is indicated by address byte with the W bit low, followed by the pulling SDA from low to high, while SCL is high. Pointer Register byte. No additional data are required. The master can then generate a START condition and send the slave address byte with the W bit high to initiate the read command. See Figure for details of this sequence. If repeated Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com TIMING DIAGRAMS SCL SDA t(LOW) tR tF t(HDST A) t(HDST A) t(HDDA T) t(BUF) t(SUDA T) t(HIGH) t(SUST A) t(SUSTO) P S S P TMP400 SBOS404 DECEMBER 2007 reads from the same register are desired, it is not Stop Data Transfer: A change in the state of the necessary to continually send the Pointer Register SDA line from low to high while the SCL line is high bytes, because the TMP400 retains the Pointer defines a STOP condition. Each data transfer Register value until it is changed by the next write terminates with a repeated START or STOP operation. Note that register bytes are sent MSB first, condition. followed by the LSB. Data Transfer: The number of data bytes transferred between a START and a STOP condition is not limited and is determined by the master device. The receiver acknowledges the transfer of data. Figure to Figure describe various operations on the TMP400. Bus definitions are given below. Acknowledge: Each receiving device, when Parameters for Figure are defined in Table addressed, is obliged to generate an Acknowledge bit. A device that acknowledges must pull down the Bus Idle: Both SDA and SCL lines remain high. SDA line during the Acknowledge clock pulse in such Start Data Transfer: A change in the state of the a way that the SDA line is stable low during the high SDA line, from high to low, while the SCL line is high, period of the Acknowledge clock pulse. Setup and defines a START condition. Each data transfer hold times must be taken into account. On a master initiates with a START condition. receive, data transfer termination can be signaled by the master generating a Not-Acknowledge on the last byte that has been transmitted by the slave. Figure 13. Two-Wire Timing Diagram Table 10. Timing Diagram Definitions for Figure FAST MODE HIGH-SPEED MODE PARAMETER MIN MAX MIN MAX UNIT SCL Operating Frequency f (SCL) 0.001 0.4 0.001 3.4 MHz Bus Free Time Between STOP and START Condition t (BUF) 600 160 ns Hold time after repeated START condition. t (HDSTA) 100 100 ns After this period, the first clock is generated. Repeated START Condition Setup Time t (SUSTA) 100 100 ns STOP Condition Setup Time t (SUSTO) 100 100 ns Data Hold Time t (HDDAT) (1) (2) ns Data Setup Time t (SUDAT) 100 ns SCL Clock LOW Period t (LOW) 1300 160 ns SCL Clock HIGH Period t (HIGH) 600 ns Clock/Data Fall Time t F 300 ns Clock/Data Rise Time t R 300 160 ns for SCL 100kHz t R 1000 160 (1) For cases with fall time of SCL less than 20ns and/or the rise time or fall time of SDA less than 20ns, the hold time should be greater than 20ns. (2) For cases with fall time of SCL less than 10ns and/or the rise or fall time of SDA less than 10ns, the hold time should be greater than 10ns. Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com Frame□2□Pointer□Register□Byte Frame□4□Data□Byte□2 Start□By Master ACK□By TMP400 ACK□By TMP400 ACK□By TMP400 Stop□By Master 1 9 1 D7 D6 D5 D4 D3 D2 D1 D0 Frame□3□Data□Byte□1 ACK□By TMP400 D7SDA (Continued) SCL (Continued) D6 D5 D4 D3 D2 D1 D0 SDA SCL 0 0 1 1 0 0 R/W P7 P6 P5 P4 P3 P2 P1 P0 /c188 /c188 Frame□1□T wo-□Wire□Slave□Address□Byte(1) Frame□2□Pointer□Register□Byte Start□By Master ACK□By TMP400 ACK□By TMP400 Frame□4□Data□Byte□1□Read□Register Start□By Master ACK□By TMP400 NACK□By Master (2) From TMP400 1 9 1 9 1 9 1 9 SDA SCL 0 0 1 R/ W P7 P6 P5 P4 P3 P2 P1 P0 SDA (Continued) SCL (Continued) 1 0 0 1 1 0 0 1 0 0 R/ W D7 D6 D5 D4 D3 D2 D1 D0 Frame□1□T Wire□Slave□Address□Bytewo- (1) Frame□3□T Wire□Slave□Address□Bytewo- (1) TMP400 SBOS404 DECEMBER 2007 (1) See Table for all available addresses. and in this example. Figure 14. Two-Wire Timing Diagram for Write Word Format (1) See Table for all available addresses. and in this example. (2) Master should leave SDA high to terminate a single-byte read operation. Figure 15. Two-Wire Timing Diagram for Single-Byte Read Format Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com Frame□2□Pointer□Register□Byte Start□By Master ACK□By TMP400 ACK□By TMP400 Frame□4□Data□Byte□1□Read□Register Start□By Master ACK□By TMP400 ACK□By Master From TMP400 1 9 1 9 1 9 1 9 SDA SCL 0 0 1 R/ W P7 P6 P5 P4 P3 P2 P1 P0 /c188 /c188 /c188 /c188 SDA (Continued) SCL (Continued) SDA (Continued) SCL (Continued) 1 0 0 1 1 0 0 1 0 0 R/ W D7 D6 D5 D4 D3 D2 D1 D0 Frame□5□Data□Byte□2□Read□Register Stop□By Master ACK□By Master From TMP400 1 9 D7 D6 D5 D4 D3 D2 D1 D0 Frame□1□T wo-Wire□Slave□Address□Byte (1) Frame□3□T wo-Wire□Slave□Address□Byte (1) Frame□1□SMBus□ALERT□Response□Address□Byte Start□By Master ACK□By TMP400 From TMP400 NACK□By Master Stop□By Master 1 9 1 9 SDA SCL ALERT 0 0 0 1 1 0 0 R/ W 1 0 0 1 1 0 0 Status Frame□2□T wo-Wire□Slave□Address□Byte (1) TMP400 SBOS404 DECEMBER 2007 (1) See Table for all available addresses. and in this example. Figure 16. Two-Wire Timing Diagram for Two-Byte Read Format (1) See Table for all available addresses. and in this example. Figure 17. Timing Diagram for SMBus ALERT Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com HIGH-SPEED MODE ALERT (PIN 11) TIMEOUT FUNCTION STBY (PIN 15) Measured T emperature ALERT□High□Limit ALERT□Low□Limit□Hysteresis ALERT SMBus□ALERT Read Read Time Read TMP400 SBOS404 DECEMBER 2007 In order for the Two-Wire bus to operate at The ALERT pin of the TMP400 is dedicated to alarm frequencies above 400kHz, the master device must functions. This pin has an open-drain output that issue a High-speed mode (Hs-mode) master code requires a pull-up resistor to V+. It can be wire-ORed (00001XXX) as the first byte after a START condition together with other alarm pins for system monitoring to switch the bus to high-speed operation. The of multiple sensors. The ALERT pin is intended for TMP400 does not acknowledge this byte, but use as an earlier warning interrupt, and can be switches the input filters on SDA and SCL and the software disabled, or masked. output filter on SDA to operate in Hs-mode, allowing The ALERT pin (pin 11) asserts low when either the transfers at up to 3.4MHz. After the Hs-mode master measured local or remote temperature violates the code has been issued, the master transmits a range limit set by the corresponding Local/Remote Two-Wire slave address to initiate a data transfer Temperature High/Low Limit Registers. This alert operation. The bus continues to operate in Hs-mode function can be configured to assert only if the range until a STOP condition occurs on the bus. Upon is violated a specified number of consecutive times receiving the STOP condition, the TMP400 switches (1, or 4). The consecutive violation limit is set in the input and output filter back to fast-mode the Consecutive Alert Register. False alerts that operation. occur as a result of environmental noise can be prevented by requiring consecutive faults. ALERT also asserts low if the remote temperature sensor is open-circuit. When the MASK function is enabled When bit of the Consecutive Alert Register is set (Configuration Register: bit 1), ALERT is disabled high, the TMP400 timeout function is enabled. The (that is, masked). ALERT resets when the master TMP400 resets the serial interface if either SCL or reads the device address, as long as the condition SDA are held low for 30ms (typical) between a that caused the alert no longer persists, and the START and STOP condition. If the TMP400 is Status Register has been reset. holding the bus low, it releases the bus and waits for a START condition. To avoid activating the timeout function, it is necessary to maintain a communication speed of at least 1kHz for the SCL operating The TMP400 a standby pin STBY that, frequency. The default state of the timeout function is when pulled low, disables the device. During normal enabled (bit high). operation STBY should be tied high (V+). When STBY is pulled low, the TMP400 is immediately disabled. If the TMP400 receives a One-Shot command when STBY is pulled low, the command is ignored and the TMP400 continues to be disabled until STBY is pulled high. Figure 18. SMBus Alert Timing Diagram Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com SMBUS ALERT FUNCTION UNDERVOLTAGE LOCKOUT GENERAL CALL RESET SHUTDOWN MODE (SD) IDENTIFICATION REGISTERS SENSOR FAULT FILTERING TMP400 SBOS404 DECEMBER 2007 The TMP400 supports the SMBus Alert function. The The TMP400 senses when the power-supply voltage ALERT pin of the TMP400 may be connected as an has reached a minimum voltage level for the ADC SMBus Alert signal. When a master detects an alert converter to function. The detection circuitry consists condition on the ALERT line, the master sends an of a voltage comparator that enables the ADC SMBus Alert command (00011001) on the bus. If the converter after the power supply (V+) exceeds 2.45V ALERT pin of the TMP400 is active, the device (typical). The comparator output is continuously acknowledges the SMBus Alert command and checked during a conversion. The TMP400 does not respond by returning its slave address on the SDA perform a temperature conversion if the power supply line. The eighth bit (LSB) of the slave address byte is not valid. The last valid measured temperature is indicates whether the temperature exceeding one of used for the temperature measurement result. the temperature high limit settings or falling below one of the temperature low limit settings caused the alert condition. This bit is high if the temperature is The TMP400 supports reset via the Two-Wire greater than or equal to one of the temperature high General Call address 00h (0000 0000b). The limit settings; this bit is low if the temperature is less TMP400 acknowledges the General Call address and than one of the temperature low limit settings. See responds to the second byte. If the second byte is Figure for details of this sequence. 06h (0000 0110b), the TMP400 executes a software If multiple devices on the bus respond to the SMBus reset, while latching the status of the address pins. Alert command, arbitration during the slave address This software reset restores the power-on reset state portion of the SMBus Alert command determines to all TMP400 registers, aborts any conversion in which device will clear its alert status. If the TMP400 progress, and clears the ALERT pin. If the second wins the arbitration, its ALERT pin becomes inactive byte is 04h 0000 0100b the TMP400 latches the at the completion of the SMBus Alert command. If the status of the address pins, but does not reset. The TMP400 loses the arbitration, the ALERT pin remains TMP400 takes no action in response to other values active. in the second byte. A 500 µ s time delay must be taken after a general call command. The TMP400 Shutdown Mode allows the user to save maximum power by shutting down all device circuitry The TMP400 allows for the Two-Wire bus controller other than the serial interface, reducing current to query the device for manufacturer and device IDs consumption to typically less than µ see typical to allow for software identification of the device at the characteristic curve Shutdown Quiescent Current vs particular Two-Wire bus address. The manufacturer Supply Voltage Figure Shutdown Mode is ID is obtained by reading from pointer address FEh. enabled when the SD bit of the Configuration The device ID is obtained by reading from pointer Register is high; the device shuts down once the address FFh. The TMP400 returns 55h for the current conversion is completed. When SD is low, the manufacturer code and 01h for the device ID. These device maintains a continuous conversion state. registers are read-only. The TMP400 senses a fault at the input resulting Remote junction temperature sensors are usually from incorrect diode connection or an open circuit. implemented in a noisy environment. Noise is most The detection circuitry consists of a voltage often created by fast digital signals, and it can corrupt comparator that trips when the voltage at exceeds measurements. The TMP400 has a built-in 65kHz (V+) 0.6V (typical). The comparator output is filter on the inputs of and D to minimize the continuously checked during a conversion. If a fault is effects of noise. However, a bypass capacitor placed detected, the result reads 7FFh (0111 1111 1111b) differentially across the inputs of the remote and is used for the temperature measurement result; temperature sensor is recommended to make the the OPEN bit (Status Register, bit is set high, and, application more robust against unwanted coupled if the alert function is enabled, ALERT asserts low. signals. The value of the capacitor should be between 100pF and 1nF. Some TMP400, better overall accuracy with additional series the and D inputs must be connected together to resistance; however, this increased accuracy is prevent meaningless fault warnings. setup-specific. When series resistance is added, the value should not be greater than Ω and resistance correction must be enabled (RC 1). Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

www.ti.com REMOTE SENSING MEASUREMENT ACCURACY AND THERMAL T =ERR n 1.008/c45 (4) T =ERR 1.004 1.008/c45 T = 1.48/c45ERR /c176 C (5) TMP400 SBOS404 DECEMBER 2007 If filtering is needed, the suggested component Base-emitter voltage 0.95V at 120 µ at the values are 100pF and Ω on each input. Exact lowest sensed temperature. values are application specific. Resistance correction Base resistance 100 Ω must be enabled to avoid offset correction. Tight control of V BE characteristics indicated by small variations in h FE (that is, to 150). Based on these criteria, two recommended The TMP400 is designed to be used with either small-signal transistors are the 2N3904 (NPN) or discrete transistors or substrate transistors built into 2N3906 (PNP). processor chips and ASICs. Either NPN or PNP transistors can be used, as long as the base-emitter junction is used as the remote temperature sense. CONSIDERATIONS Either a transistor or diode connection can also be used; see Figure The temperature measurement accuracy of the TMP400 depends on the remote and/or local Errors in remote temperature sensor readings are temperature sensor being at the same temperature generally the consequence of the ideality factor and as the system point being monitored. Clearly, if the current excitation used by the TMP400 versus the temperature sensor is not in good thermal contact manufacturer-specified operating current for a given with the part of the system being monitored, then transistor. Some manufacturers specify a high-level there will be a delay in the response of the sensor to and low-level current for the temperature-sensing a temperature change in the system. For remote substrate transistors. The TMP400 uses µ A for I LOW temperature sensing a substrate and 120 µ A for I HIGH The TMP400 allows for different transistor (or a small, SOT23 transistor) placed close n -factor values; see the N-Factor Correction Register to the device being monitored, this delay is usually section. not a concern. The ideality factor n is a measured characteristic of The local temperature sensor inside the TMP400 a remote temperature sensor diode as compared to monitors the ambient air around the device. The an ideal diode. The ideality factor for the TMP400 is thermal time constant for the TMP400 is trimmed to be 1.008. For transistors whose ideality approximately two seconds. This constant implies factor does not match the TMP400, Equation can that if the ambient air changes quickly by 100 it be used to calculate the temperature error. Note that would take the TMP400 about seconds (that is, for the equation to be used correctly, actual five thermal time constants) to settle to within C of temperature must be converted to Kelvin K). the final value. In most applications, the TMP400 package is in electrical (and therefore, thermal) contact with the printed circuit board (PCB), as well as subjected to forced airflow. The accuracy of the Where: measured temperature directly depends on how accurately the PCB and forced airflow temperatures n Ideality factor of remote temperature sensor represent the temperature that the TMP400 is actual temperature measuring. Additionally, the internal power dissipation T ERR Error in TMP400 reading due to n 1.008 of the TMP400 can cause the temperature to rise Degree delta is the same for C and K above the ambient or PCB temperature. The internal power dissipated as a result of exciting the remote For n 1.004 and 100 temperature sensor is negligible because of the small currents used. For a 5.5V supply and maximum conversion rate of eight conversions per second, the TMP400 dissipates 1.82mW (PD IQ 5.5V 420 µ A). If the ALERT pin is sinking 1mA, an additional power of 0.4mW is dissipated (PD OUT 1mA 0.4V If a discrete transistor is used as the remote 0.4mW). Total power dissipation is then 2.22mW temperature sensor with the TMP400, the best (PD IQ PD OUT and, with an θ JA of 150 C/W, causes accuracy can be achieved by selecting the transistor the junction temperature to rise approximately according to the following criteria: 0.333 C above the ambient. Base-emitter voltage 0.25V at µ at the highest sensed temperature. Copyright 2007, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TMP400

www.ti.com LAYOUT CONSIDERATIONS GND(1) (1) D/c45(1) GND (1) Ground□or□V+□layer on□bottom□and/or top,□if□□possible. TMP400

0.1 F□Capacitor/c109

PCB□Via PCB□Via V+ GND 8 9 TMP400 SBOS404 DECEMBER 2007 Remote temperature sensing on the TMP400 measures very small voltages using very low currents; therefore, noise at the IC inputs must be minimized. Most content, with several clocks and logic level transitions creating a noisy environment. Layout should adhere to the following guidelines: Place the TMP400 as close to the remote junction sensor as possible. Route the and D traces next to each other and shield them from adjacent signals through the use of ground guard traces, as shown in Figure If a multilayer PCB is used, bury these traces between ground or V DD planes to shield them from extrinsic noise sources. mil (0.127mm) PCB traces are recommended. (1) 5mil traces with 5mil spacing. Minimize additional thermocouple junctions caused by copper-to-solder connections. If these Figure 19. Example Signal Traces junctions are used, make the same number and approximate locations of copper-to-solder connections in both the and D connections to cancel any thermocouple effects. Use a 0.1 µ F local bypass capacitor directly between the and GND of the TMP400, as shown in Figure Minimize filter capacitance between and D to 1000pF or less for optimum measurement performance. This capacitance includes any cable capacitance between the remote temperature sensor and TMP400. If the connection between the remote temperature sensor and the TMP400 is less than inches (203.2mm), use a twisted-wire pair connection. Beyond inches, use a twisted, shielded pair with the shield grounded as close to the TMP400 as possible. Leave the remote sensor connection end of the shield wire open to Figure 20. Suggested Bypass Capacitor avoid ground loops and 60Hz pickup. Placement Submit Documentation Feedback Copyright 2007, Texas Instruments Incorporated Product Folder Link(s): TMP400

Orderable Device Status(1) Package Type Package Drawing Pins Package Qty Eco Plan(2) Lead/Ball FinishMSL Peak Temp (3) TMP400AIDBQR ACTIVE SSOP/ QSOP DBQ 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TMP400AIDBQT ACTIVE SSOP/ QSOP DBQ 16 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR (1)The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2)Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontentfor the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS):TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt):This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br):TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. PACKAGE OPTION ADDENDUM www.ti.com 21-Dec-2007 Addendum-Page 1

TAPE AND REEL BOX INFORMATION Device Package Pins Site Reel Diameter (mm) Reel Width (mm) A0 (mm) B0 (mm) K0 (mm) P1 (mm) W (mm) Pin1 Quadrant TMP400AIDBQR DBQ 16 SITE 41 330 12 6.4 5.2 2.1 8 12 Q1 TMP400AIDBQT DBQ 16 SITE 41 180 12 6.9 5.4 2.0 8 12 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 19-Dec-2007 Pack Materials-Page 1

Device Package Pins Site Length (mm) Width (mm) Height (mm) TMP400AIDBQR DBQ 16 SITE 41 346.0 346.0 29.0 TMP400AIDBQT DBQ 16 SITE 41 184.0 184.0 50.0 PACKAGE MATERIALS INFORMATION www.ti.com 19-Dec-2007 Pack Materials-Page 2

(TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for design. Customers are responsible for their products and components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional restrictions. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. TI products are not authorized for use in safety-critical (such as life support) where a failure of the TI product would reasonably be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in such safety-critical applications. TI products are neither designed nor intended for use in military/aerospace "enhanced plastic." Only products designated by TI as military-grade meet military specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use. TI products are neither designed nor intended for use in automotive requirements. Buyers acknowledge and agree that, if they use any non-designated products in automotive applications, TI will not be responsible for any failure to meet such requirements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products amplifier.ti.com Audio www.ti.com/audio Data Converters dataconverter.ti.com Automotive www.ti.com/automotive DSP dsp.ti.com Broadband www.ti.com/broadband Interface interface.ti.com Digital Control www.ti.com/digitalcontrol Logic logic.ti.com Military www.ti.com/military Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork Microcontrollers microcontroller.ti.com Security www.ti.com/security RFID www.ti-rfid.com Telephony www.ti.com/telephony Low Power www.ti.com/lpw Video Imaging www.ti.com/video Wireless Wireless www.ti.com/wireless Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright 2007, Texas Instruments Incorporated