FM75 Fairchild Semiconductor, FM75 Datasheet
FM75
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FM75 Summary of contents
Page 1
... Address SMBus Interface 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 ...
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... A0, A1, A2 Input 8 V Supply DD 2 SDA SCL FM75 O. GND Description Serial Clock. Clock for 2-wire serial interface. Over-Limit Signal. Open drain thermostat output that indicates if the temperature has exceeded user-programmable limits. Default is active low. Ground Address LSBs. User selectable address pins for the 3 LSBs of the serial interface address ...
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... 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. ...
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... Data Out Stable after SCL Low SCL Low Set-up to SDA Low (Repeated Start Condition) SCL High Hold after SDA Low (Start Condition) SDA High after SCL High (Stop Condition Time in which a FM75 must be operational after a power-on reset SCL t HD:STA SDA Data In ...
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... If the sign bit is a zero, the temperature is positive and if the sign bit is a one, the temperature is negative. The FM75 has a Shutdown Mode that reduces the operating current of the FM75 to 150nA. This mode is controlled by the SD bit in the configuration register. Power Up Default Conditions The FM75 always powers up in the following default state: • ...
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... T OS (similar to Comparator Mode). Once O.S. is active, it can only be cleared by a user read from any of the FM75 registers (Temperature, Configuration, T putting the FM75 into Shutdown Mode (i.e., by setting the shutdown bit in the Configuration Register to “1”). Once cleared, the O ...
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... PRODUCT SPECIFICATION Registers The FM75 contains the following five registers: 1. Command Register 2. Temperature Register 3. Configuration Register 4. Over-Limit-Signal Temperature Register (T 5. Hysteresis Temperature Register (T All of these registers can be accessed by the user via the digital serial interface at any time (see Serial Interface Operation for instructions) ...
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... The Configuration Register is a one-byte (8-bit) read/write register (see Figure 5). This register allows the user to control the FM75 Shutdown Mode as well as the following thermal alarm features: polarity, operating mode, and fault tolerance. The Configuration Register contains two bits that set the fault tolerance trip point ...
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... LSB = Temperature LSB for 10-bit conversions 11-bit LSB = Temperature LSB for 11-bit conversions 12-bit LSB = Temperature LSB for 12-bit conversions Register and T Register Format HYST OS ) HYST register are hardwired to zero, so HYST Register are used by the thermal HYST Register, HYST LSB 0 0 FM75 9 ...
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... 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 ...
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... Inadvertent 8-Bit Read from a 16-Bit Register: A Caution An inadvertent 8-bit read from a 16-bit register, with the D7 bit low, can cause the FM75 to pause in a state where the SDA line is pulled low by the output data and is incapable of receiving either a stop or a start condition from the master. ...
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... Ack from FM75 PRODUCT SPECIFICATION . . . . . . . . P0 A Ack from aTS75 Ack from Least Significant Data Byte Master (from FM75 Register) OS HYST Ack from Least Significant Data Master Byte (from FM75 Register) ...
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... Ack Repeat Start from from FM75 Address Byte Master Ack from Data Byte Master (from FM75 Ack from Data Byte FM75 (from Master) FM75 R Ack from FM75 13 ...
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... FM75 Mechanical Dimensions 0.150 - 0.157 (3.810 - 3.988) 0.010 - 0.020 x 45° (0.254 - 0.508) 0.004 0.0075 - 0.0098 (0.102) (0.190 - 0.249) All lead tips Typ. All Leads Molded Package, Small Outline, 0.15 Wide, 8-Lead (M8) 0.118 - 0.004 8 0.193 ± 0.004 [4.9 ± 0.1] PIN 1 IDENT 1 0.030 - 0.037 [0.78 - 0.94] – ...
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... Ordering Information Part Number Package FM75M8x 8-Lead SOIC FM75MM8x 8-Lead MSOP 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; ...