DS7505 MAXIM | Alldatasheet
Document overview
- Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 14
Technical content
Features
o Operating Range from 1.7V to 3.7V o Temperature Measurements Require No External Components o Measures Temperatures from -55°C to +125°C (-67°F to +257°F) o ±0.5°C Accuracy Over a 0°C to +70°C Range o Thermometer Resolution is User-Configurable from 9 (Default) to 12 Bits (0.5°C to 0.0625°C Resolution) o 9-Bit Conversion Time is 25ms (max) o Thermostatic Settings are User-Definable and Nonvolatile (NV) o Stand-Alone Thermostat Capability o Data Read/Write Occurs Through a 2-Wire Serial Interface (SDA and SCL Pins) o Data Lines Filtered Internally for Noise Immunity (50ns Deglitch) o Optional Bus Timeout Feature Prevents Lockup Problems on 2-Wire Interface o Multidrop Capability Simplifies Distributed Temperature-Sensing Applications o Pin/Software Compatible with the LM75 o Available in 8-Pin SO and µMAX® Packages DS7505 Digital Thermometer and Thermostat SO TOP VIEW
27 A 0SCL
A1O.S. 3 6 A2GND 45 DS7505 µµMAX A1O.S. 3 6 A2GND 4 5 DS7505□ Pin Configurations
Ordering Information
Rev 1; 3/08 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. PART TEMP RANGE PIN-PACKAGE DS7505S+ -55°C to +125°C 8 SO (150 mils) DS7505S+T&R -55°C to +125°C 8 SO (150 mils) , 2500-Piece T&R DS7505U+ -55°C to +125°C 8 µMAX DS7505U+T&R -55°C to +125°C 8 µMAX, 3000-Piece T&R +Denotes a lead-free package. T&R = Tape and reel. µMAX is a registered trademark of Maxim Integrated Products, Inc. Commands are capitalized for clarity.
Digital Thermometer and Thermostat ABSOLUTE MAXIMUM RATINGS DC ELECTRICAL CHARACTERISTICS (1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C, unless otherwise noted.) Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Voltage Range on Any Other Pin J-STD-020 Specification. PARAMETER SYMBOL CONDITIONS MIN MAX UNITS Supply Voltage V DD 1.7 3.7 V Input Voltage Range (SDA, SCL, O.S., A0, A1, A2) (Note 1) -0.3 +5.5 V 0°C to +70°C ± 0.5Thermometer Error (Note 2, 3) TERR Input Logic-High V IH (Note 1) 0.7 × V DD V Input Logic-Low V IL (Note 1) 0.3 × V DD V SDA Output Logic-Low Voltage V OL1 6mA sink current (Note 1) 0 0.6 V O.S. Saturation Voltage V OL2 4mA sink current (Notes 1, 2) 0.8 V Input Current Each I/O pin 0.4V < V I/O < 0.9 x V DD -10 +10 µA I/O Capacitance C I/O 10 pF Standby Current I DD1 (Notes 4, 5, 6) 2 µA Active temp conversions 750 Communicatio n only 100Active Current (Notes 4, 5, 6) IDD E2 Copy only 500 µA AC ELECTRICAL CHARACTERISTICS (1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Resolution 9 12 Bits 9-bit conversions 25 10-bit conversions 50 11-bit conversions 100 Temperature Conversion Time t CONVT 12-bit conversions 200 ms SCL Frequency f SCL 400 kHz EEPROM Copy Time t WR -40°C to +85°C 10 ms -40°C T A +85°C (Note 7) 10k 20kEEPROM Copy Endurance N EEWR TA = +25°C (Note 7) 40k 80k Cycles
Digital Thermometer and Thermostat Note 1: All voltages are referenced to ground. max-rated current. Note 3: Specified in 12-bit conversion mode. Quantization error must be considered when converting in lower resolutions. Note 4: IDD specified with O.S. pin open. Note 5: IDD specified with VDD at 3.0V and SDA, SCL = 3.0V, TA = -55°C to +85°C. Note 6: IDD specified with A0, A1, A2 = 0V or VDD. Note 7: VDD must be > 2.0V. Note 8: E2 Copy occurs at +25°C. Note 9: See the timing diagram (Figure 1). All timing is referenced to 0.9 x VDD and 0.1 x VDD. Note 10: After this period, the first clock pulse is generated. Note 11: The DS7505 provides an internal hold time of at least 75ns on the SDA signal to bridge the undefined region of SCL’s falling edge. Note 12: For example, if CB = 300pF, then tR(MIN) = tF(MIN) = 50ns. Note 13: This timeout applies only when the DS7505 is holding SDA low. Other devices can hold SDA low indefinitely and the DS7505 does not reset. AC ELECTRICAL CHARACTERISTICS (continued) (1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS EEPROM Data Retention t EEDR -40°C to +125°C (Note 8) 10 Years Bus Free Time Between a STOP and START Condition tBUF (Note 9) 1.3 µs START and Repeated START Hold Time from Falling SCL tHD:STA (Notes 9, 10) 600 ns Low Period of SCL t LOW (Note 9) 1.3 µs High Period of SCL t HIGH (Note 9) 0.6 µs Repeated START Condition Setup Time to Rising SCL tSU:STA (Note 9) 600 ns Data-Out Hold Time from Falli ng SCL tHD:DAT (Notes 9, 11) 0 0.9 µs Data-In Setup Time to Rising tSU:DAT (Note 9) 100 ns Rise Time of SDA and SCL (Receive) tR (Notes 9, 12) 20 + 0.1C B 300 ns Fall Time of SDA and SCL (Receive) tF (Notes 9, 12) 20 + 0.1C B 300 ns Spike Suppression Filter Time (Deglitch Filter) tSS 0 50 ns STOP Setup Time to Ris ing SCL t SU:STO (Note 9) 600 ns Capacitive Load for Each Bus Line CB 400 pF Input Capacitance C I 5 pF Serial Interface Reset Time t TIMEOUT SDA time low (Note 13) 75 325 ms
1 SDA Data Input/Output. For 2-wire serial communication port. Open drain. 2 SCL Clock Input. For 2-wire serial communication port. 3 O.S. Thermostat Output. Open drain.
4 GND Ground
5 A2 Address Input
6 A1 Address Input
7 A0 Address Input
8 VDD Supply Voltage. +1.7V to +3.7V supply pin. Figure 1. Timing Diagram Figure 2. Block Diagram
Figure 3. Temperature, TOS, and THYST Register Format Table 1. 12-Bit Resolution Temperature/Data Relationship components to measure temperature. sion time doubles for each additional bit of resolution. can be read from the temperature register at any time. affect the operation in progress. perature register contain data, and bit 4 reads out as 0. ital output data and the corresponding temperatures.
For power-sensitive applications, the DS7505 offers a low-power shutdown mode. The SD bit in the configura- tion register controls shutdown mode. When SD is pro- grammed to 1, the conversion in progress is completed and the result stored in the temperature register, after which the DS7505 goes into a low-power standby state. The O.S. output is cleared if the thermostat is operating in interrupt mode and O.S remains unchanged in com- parator mode. The 2-wire interface remains operational in shutdown mode, and writing a 0 to the SD bit returns the DS7505 to normal operation. Upon power-up in shutdown mode, the DS7505 executes one tempera- ture measurement. The result is stored in the tempera- ture register, after which the DS7505 enters the shutdown state. Operation Thermostat The DS7505 thermostat can be programmed to power up in either comparator mode or interrupt mode, which activate and deactivate the open-drain thermostat out- put (O.S.) based on user-programmable trip points OS and THYST). The THYST and TOS registers contain Celsius temperature values in two’s complement format and consist of EEPROM that is shadowed by SRAM. Once written to the shadow SRAM, values can be stored in EEPROM by issuance of a Copy Data com- mand from the master (see the Command Set section for more details). The device can operate using the shadow SRAM only or using the EEPROM. If the EEPROM is used, the values are NV and can be pro- grammed prior to installation of the DS7505 for stand- alone operation. The factory power-up settings for the DS7505 are with the thermostat in comparator mode, active-low O.S. polarity, overtemperature trip-point OS) register set to 80°C, the hysteresis trip-point (THYST) register set to +75°C, and the number of con- secutive conversion to trigger O.S. set to 1. If these power-up settings are compatible with the application, the DS7505 can be used as a stand-alone thermostat (i.e., no 2-wire communication required) with no pro - gramming required prior to installation. If interrupt mode operation, active-high O.S. polarity, different T OS and THYST values, or a different number of conversions to trigger O.S. are desired, they must be programmed into the EEPROM either after initial power-up or prior to IC installation. The programmed values then become the new power-up defaults. In both operating modes, the user can program the thermostat-fault tolerance, which sets how many con- secutive temperature readings (1, 2, 4, or 6) must fall outside the thermostat limits before the thermostat out- put is triggered. The fault tolerance is set by the F1 and F0 bits in the configuration register. The default factory power-up setting for fault tolerance is 1 (F1 = 0, F0 = 0). The data format of the T OS and THYST registers is iden- tical to that of the temperature register (see Figure 3), i.e., a 2-byte two’s complement representation of the trip-point temperature in degrees Celsius with bits 3 through 0 hardwired to 0. After every temperature con- version, the measurement is compared to the values stored in the T OS and THYST registers. The O.S. output is updated based on the result of the comparison and the operating mode of the IC. The number of T OS and THYST bits used during the thermostat comparison is equal to the conversion resolution set by the R1 and R0 bits in the configuration register. For example, if the resolution is 9 bits, only the 9 MSBs of T OS and THYST are used by the thermostat comparator. The active state of the O.S. output can be programmed by the POL bit in the configuration register. The power- up factory default is active low (POL = 0). If the user does not wish to use the thermostat capabili- ties of the DS7505, the O.S. output should be left unconnected. Note that if the thermostat is not used, the T OS and T HYST registers can be used for general storage of system data. Comparator Mode When the thermostat is in comparator mode, O.S. can be programmed to operate with any amount of hystere- sis. The O.S. output becomes active when the mea- sured temperature exceeds the T OS value a consecutive number of times as defined by the F1 and F0 fault tolerance (FT) bits in the configuration register. O.S. then stays active until the first time the tempera - ture falls below the value stored in T HYST. Putting the device into shutdown mode does not clear O.S. in com- parator mode. Thermostat comparator mode operation with FT = 2 is illustrated in Figure 4. Digital Thermometer and Thermostat
TO HAVE A FAULT TOLERANCE OF 2. Figure 4. O.S. Output Operation Example value in the configuration register. Once activated, O.S. OS, or T HYST) on the device. device into shutdown mode or reading any register. mode operation with FT = 2 is illustrated in Figure 4.
- The user has read/write access to all bits in the con-
and powers up in the state shown in Table 2. Figure 5. Configuration Register Table 2. Configuration Register Bit Descriptions NVB = 1—Wr ite to an NV memory cell is in progress. NVB = 0—NV memory is not busy. Sets conversio n resolution (see Table 3). Sets conversio n resolution (see Table 3). Sets the thermostat fault tolerance (see Table 4). Sets the thermostat fault tolerance (see Table 4). POL = 0—O .S. is active low. POL = 1—O. S. is active high. See the Operation— Thermostat section for a detailed description of these modes. SD = 0—A ctive conversion and thermostat operation. See the Shutdown Mode section for a detailed description of this mode.
immediately without resetting the pointer. 2-Wire Serial Data Bus section. open-drain SDA I/O pin. All communication is MSB first. Slave: All devices on the bus other than the master. The DS7505 always functions as a slave. Bus Idle or Not Busy: Both SDA and SCL remain high. pullup resistor (if the SCL output is open drain). indicate the beginning of a data transfer on the bus. SDA from high to low while SCL is high (see Figure 6). master performs another operation. Table 3. Resolution Configuration Table 4. Fault Tolerance Configuration Table 5. Pointer Definition
2 A1 A0, where A 2, A1, and A 0 are user-selectable
respond to the desired register as shown in Figure 8. Figure 7. Address Byte Figure 8. Pointer Byte Figure 6. Start, Stop, and ACK Signals
sent by the IC after the POR command is received. depending on the state of the SD bit. Figure 9. 2-Wire Interface Timing
Digital Thermometer and Thermostat
Package Information
(For the latest package outline information, go to www.maxim-ic.com/DallasPackInfo.) 21-0036 PACKAGE TYPE DOCUMENT NO.
8 SO (150 mils) 56-G2008-001
8 µMAX
Digital Thermometer and Thermostat Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Revision History
0 2/08 Initial relea se. — 1 3/08 Removed references to exposed pad (µMAX package does not have an EP); corrected package information outline document number. 1, 4, 13