FM75 FAIRCHILD | Alldatasheet

Document overview

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Technical content

Features

  • User Configurable to 9, 10, 11 or 12-bit Resolution
  • Precision Calibrated to ±1°C from 0°C to 100°C Typical
  • T emperature Range: –40°C to 125°C
  • L ow Operating Current (less than 250µA)
  • L ow Self Heating (0.2°C max in still air)
  • Operating V oltage Range: 2.7V to 5.5V

Applications

  • Battery Management
  • F AX Management
  • Printers
  • Portable Medical Instruments
  • H V A C
  • P ower Supply Modules
  • Disk Drives
  • Computers
  • Automotive

Description

Within the FM75 are: a high-precision CMOS temperature sensor, a Delta-Sigma analog-to-digital converter and a SMBus compatible serial digital interface. Typical accuracy is ±2°C over the full temperature range of –40°C to 125°C and to ±1°C over the range of 0°C to 100°C, with 9- to 12-bit resolution. Default resolution is 9 bits. Thermal Alarm output, OS (Over-limit Signal) supports Interrupt and Comparator modes. OS is active, if the user-programmable trip-temperature is exceeded. When the temperature falls below the trip-temperature plus the user-programmable hysteresis limit, OS is disabled. Available packages are surface mount SOIC-8 (SOP-8) and MSOP-8. Application Diagram FM75 SDA SCL O.S.

8 Pin

2.7 to 5.5V FM75 Low Voltage 2-Wire Digital Temperature Sensor with Thermal Alarm

FM75 PRODUCT SPECIFICATION REV. 1.0.5 10/2/03 Pin Assignments Pin Descriptions Pin # Name Direction Description 1S DA Input/Output Serial Data. Open drain to I/O-data pin for two-wire interface.

2 SCL Input

Serial Clock. Clock for 2-wire serial interface. 3O .S. Output Over-Limit Signal. Open drain thermostat output that indicates if the temperature has exceeded user-programmable limits. Default is active low.

4 GND Supply

5, 6, 7 A0, A1, A2 Input Address LSBs. User selectable address pins for the 3 LSBs of the serial interface address. DD Supply Supply Voltage VDD SDA SCL O.S. GND FM75

PRODUCT SPECIFICATION FM75 REV. 1.0.5 10/2/03 Absolute Maximum Ratings Notes: 1. Absolute maximum ratings are limits beyond which operation may cause permanent damage to the device. These are stress ratings only; functional operation at or above these limits is not implied. 2. Human Body Model: 100pF capacitor discharged through a 1.5k Ω resistor into each pin. Machine Model: 200pF capacitor discharged directly into each pin.

Electrical Characteristics

(-40°C T A +125°C, V CC = 5.0V unless otherwise noted. Specifications subject to change without notice.) Notes: 3. These specifications are guaranteed only for the test conditions listed. 4. This specification only indicates how often temperature information is updated to the Temperature Register. The FM75 can be read at any time without interrupting the temperature conversion process. 5. Accuracy (expressed in °C) = Difference between the FM75 output temperature and the measured temperature. Logic Electrical Characteristics Parameter Min. Typ. Max. Units Supply Voltage +7 V Output Voltage V CC + 0.5 V Output Current 10 mA Storage Temperature Range -60 +150 °C Lead Soldering Temperature 220 °C ESD Human Body Model Machine Model 2000 250 V V Parameter Symbol Conditions Min. Typ. Max. Units Specified Temperature Range T MIN , T MAX -40 +125 °C Temperature Conversion Time 90 ms Accuracy T A = +25°C T A = +100°C T A = –40°C (T MIN T A = +125°C (T MAX Parameter Symbol Conditions Min Typ Max Units Min. Input Voltage Logic High V IH V DD x 0.7 V DD + 0.5 V Max. Input Voltage Logic Low V IL -0.3 V DD x 0.3 V Max. Output Voltage Logic Low V OL V DD = 5V, I OL = -3mA V DD = 3V, I OL = -1.5mA 0.36 0.36 V V Quiescent Supply Current I DD Interface inactive R/W Activity on SDA 250 350 500 700 µA Shutdown Current I DD-SD Interface inactive R/W Activity on SDA 0.15 150 µA Input Leakage Current I IN V IN = 0V or 5V, T A = 25°C -40°C < T A < 125°C ±0.1 ±1.0 µA Output Sink Current I OL T A = 25°C, V OL = 0.4V 3 mA Output Leakage Current I LEAK V OH = 5V, V DD = 0V 0.001 5 µA Output Transition Time t F C L = 400pF, I OL = -3mA 250 ns Input Capacitance C IN All Digital Inputs 20 pF

FM75 PRODUCT SPECIFICATION REV. 1.0.5 10/2/03 Serial Port Timing Parameter Symbol Conditions Min. Typ. Max. Units SCL Clock Period t SCL 1.0 100 µs SCL Clock Transition Time t T:LH , t T:HL 300 ns SCL Clock Low Period t LOW 0.470 µs SCL Clock High Period t HIGH 0.400 50 µs Bus free time between a Stop and a new Start Condition t BUF 1.0 µs Data in Set-up to SCL High t SU:DAT 100 ns Data Out Stable after SCL Low t HD:DAT 0n s SCL Low Set-up to SDA Low (Repeated Start Condition) t SU:STA 100 ns SCL High Hold after SDA Low (Start Condition) t HD:STA 100 ns SDA High after SCL High (Stop Condition t SU:STO 100 ns Time in which a FM75 must be operational after a power-on reset t POR 500 ms SDA Data In tHD:STA tSCL tSU:STOtSU:DAT tHD:DAT SCL SDA Data Out SCL 10% 10% 90% tT:LH tT:HLtLOW tHIGH tBUF tSU:STA 90%

placed into the temperature register. by the R0 and R1 bits in the Configuration Register. temperature information for each conversion accuracy. the most significant bit of the temperature is the “sign” bit. sign bit is a one, the temperature is negative. the SD bit in the configuration register.

  • Thermostat mode: Comparator Mode
  • O.S. polarity: active low
  • F ault tolerance: 1 fault (i.e., F0 = 0 and F1 = 0 in the Configuration Register) OS = 80°C HYST = 75°C
  • R egister pointer: 00 (Temperature Register)
  • Conversion resolution: 9 bits (i.e., R0 = 0 and R1 = 0 in the Configuration Register) After power up these conditions can be reprogrammed via the serial interface. Refer to the Serial Data Bus Operation section for FM75 programming instructions. Thermal Alarm Function The FM75 thermal alarm function provides user program- mable thermostat capability and allows the FM75 to function as a stand alone thermostat without using the serial interface. The Over-Limit Signal (O.S.) output is the alarm output. This signal is an open drain output, and at power-up this pin is configured with active-low polarity.

Table 1. Relationship Between Temperature and CMP/INTR bit in the Configuration Register. tolerance” setting plays a role in determining when the O.S. help eliminate false alarms caused by noise in the system. power-up, these bits both default to 0 (fault tolerance = 1).

register, the O.S. output will be activated. Mode with fault tolerance=2 is illustrated in Figure 1. Figure 1. Thermal Alarm Operation in Comparator and Interrupt Modes

intervals—i.e., each time the T-to-D conversion is finished. 11 or 12 MSBs of the register will contain temperature data. Register default to zero at power-up. Figure 4. Temperature Register Format alarm features: polarity, operating mode, and fault tolerance. the configuration register default to zero at power-up. POL = O.S. output polarity. 0 = active low, 1 = active high. Figure 5. Configuration Register Format Table 3. Conversion Resolution Settings Table 4. Fault Tolerance Settings

7 LSB6 5 4 3 2 1

9 Bits 0 0

10 Bits 0 1

11 Bits 1 0

12 Bits 1 1

bit 14 contains the temperature MSB. this register is the same as that of the Temperature Register. data written to these bits is ignored. Figure 6. T

FM75 PRODUCT SPECIFICATION 10 REV. 1.0.5 10/2/03 Serial Data Bus Operation General Operation Writing to and reading from the FM75 registers is accom- plished via the SMBus-compatible two-wire serial interface. SMBus protocol requires that one device on the bus initiates and controls all read and write operations. This device is called the “master” device. The master device also generates the SCL signal which is the clock signal for all other devices on the bus. All other devices on the bus are called “slave” devices. The FM75 is a slave device. Both the master and slave devices can send and receive data on the bus. During SMBus operations, one data bit is transmitted per clock cycle. All SMBus operations follow a repeating nine clock-cycle pattern that consists of eight bits (one byte) of transmitted data followed by an acknowledge (ACK) or not acknowledge (NACK) from the receiving device. Note that there are no unused clock cycles during any operation— therefore there must be no breaks in the stream of data and ACKs/NACKs during data transfers. Conversely having too few clock cycles can lead to incorrect operation if an inadvertent 8-bit read from a 16-bit register occurs. For most operations, SMBus protocol requires the SDA line to remain stable (unmoving) whenever SCL is high—i.e., transitions on the SDA line can only occur when SCL is low. The exceptions to this rule are when the master device issues a start or stop signal. Note that the slave device cannot issue a start or stop condition. The following are definitions for some general SMBus terms: Start Condition: This condition occurs when the SDA line transitions from high to low while SCL is high. The master device uses this condition to indicate that a data transfer is about to begin. Stop Condition: This condition occurs when the SDA line transitions from low to high while SCL is high. The master device uses this condition to signal the end of a data transfer. Acknowledge and Not Acknowledge: When data is trans- ferred to the slave device it sends an acknowledge (ACK) after receiving every byte of data. A master device sends an acknowledge (ACK) following only the first byte read from a 2-byte register. The receiving device sends an ACK by pulling SDA low for one clock. Following the last byte, a master device sends a “not acknowledge” (NACK) followed by a stop condition. A NACK is indicated by leaving SDA high during the clock after the last byte. Slave Address Each slave device on the bus has a unique 7-bit address so the master can identify which device is being read from or written to. The FM75 address is as follows: The four MSBs of the FM75 address are hardwired to 1001. The three LSBs are user configurable by tying the A0, A1 and A2 pins to either V DD or ground. This provides eight different FM75 addresses, which allows up to eight FM75s to be connected to the same bus. Writing To and Reading From the FM75 All read and write operations must begin with a start signal generated by the master device. After the start condition, the master device must immediately send a slave address (7 bits) followed by a read/write bit. If the slave address matches the address of the FM75, the FM75 sends an ACK after receiving the read/write bit by pulling the SDA line low for one clock. See Figure 8 through Figure 13 for timing diagrams for all FM75 operations. Setting the Pointer For all operations the pointer stored in the Command Register must be pointing to the register (Temperature, Configuration, T OS or THYST) that is going to be written to or read from. To change the pointer value in the Command Register, the read/write bit following the address must be 0. This indicates that the master will now write new informa- tion into the Command Register. After the FM75 sends an ACK in response to receiving the address and read/write bit, the master device must transmit an appropriate 8-bit pointer value as explained in the Registers section of this data sheet. The FM75 will send an ACK after receiving the new pointer data. The pointer set operation is illustrated in Figure 8. Anytime a pointer set is performed, it must be immediately followed by a read or write operation. Note that the 6 MSBs of the pointer value must be zero. If the 6 MSBs are not zero, the FM75 will not send an ACK and will internally terminate the operation. Also recall that the Command Register retains the current pointer value between operations. Therefore, once a register is being pointed to, subsequent read operations do not require a pointer set cycle. Write operations always require the pointer be reset. 1 0 0 1A 1A2 A0

Figure 11. Pointer Set Followed by Immediate Write to A 2-byte Register (TOS or THYST Register) Figure 12. Pointer Set Followed by Immediate Read from Configuration Register Figure 13. Pointer Set Followed by Immediate Write to the Configuration Register

000000 P 1 P0A2 A1 A0

FM75 PRODUCT SPECIFICATION 14 REV. 1.0.5 10/2/03 Mechanical Dimensions inches (millimeters) unless otherwise noted Molded Package, Small Outline, 0.15 Wide, 8-Lead (M8) 8-Lead Molded Mini Small Outline Package (MSOP), JEDEC MO-187, 3.0mm Wide 1234 8765 0.189 - 0.197 (4.800 - 5.004) 0.228 - 0.244 (5.791 - 6.198) Lead #1 IDENT Seating Plane 0.004 - 0.010 (0.102 - 0.254) 0.014 - 0.020 (0.356 - 0.508) 0.014 (0.356) Typ. 0.053 - 0.069 (1.346 - 1.753) 0.050 (1.270) Typ 0.016 - 0.050 (0.406 - 1.270) Typ. All Leads 8° Max, Typ. All leads 0.150 - 0.157 (3.810 - 3.988) 0.0075 - 0.0098 (0.190 - 0.249) Typ. All Leads 0.004 (0.102) All lead tips 0.010 - 0.020 0.118 - 0.004 [3 ± 0.1] 0.193 ± 0.004 [4.9 ± 0.1] 0.118 ± 0.004 [3 ± 0.1] (0.189) [4.8] (0.040) [1.02] SYMM C LAND PATTERN RECOMMENDATION 0.030 - 0.037 [0.78 - 0.94] 0.021 ± 0.005 [0.53 ± 0.12] 0.007 ± 0.002 [0.18 ± 0.05] 0.002 - 0.006 [0.06 - 0.15] 0.012 ± 0.002 [0.3 ± 0.05] (0.033) [0.84] 0.0375 [0.953] PIN 1 IDENT TYP TYP TYP (0.016) [0.41] TYP 0.005 [0.13] TYP TYP GAGE PLANE R 0.005 [0.13] TYP TYP R (0.0256) [0.65] TYP 0°–6° TYP SEATING PLANE (0.0256) [0.65] –A– –B– –C– 0.002 [0.05] 0.002 [0.05] MS A C SB (0.010) [0.23]

FM75 PRODUCT SPECIFICATION 10/2/03 0.0m 003 Stock#DS30000075 2002 Fairchild Semiconductor Corporation LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.

Ordering Information

Part Number Package Temperature Range Shipping FM75M8x 8-Lead SOIC -40°C to +125°C 2500 Units, Tape and Reel FM75MM8x 8-Lead MSOP -40°C to +125°C 3000 Units, Tape and Reel