Hardware monitor with local and remote sensing
The Texas Instruments LM87CIMT/NOPB is a system hardware monitor IC in a 24-TSSOP package, combining an internal temperature sensor with support for one external diode-connected transistor for remote junction sensing. It integrates an ADC (sigma-delta), a comparator, a fan speed counter, and a register bank, with a 2-wire I²C/SMBUS serial interface for reading temperature data and controlling the fan output. The local sensor achieves ±3°C typical accuracy; the remote channel is rated ±4°C maximum, which is adequate for monitoring CPU or GPU die temperature in computing and telecom equipment where the external diode is placed near the hot spot.
Operating from a 2.8 V to 3.8 V supply, the LM87CIMT/NOPB fits into a 3.3 V logic rail environment common in server and base-station management controllers. Both the sensing and operating temperature ranges span -40°C to 125°C, covering industrial ambient conditions and the junction temperature of the monitored device.