Temperature monitor for microprocessor systems

Measuring the temperature of itself and the temperature of a remote sensor, the NE1617A is an accurate two-channel temperature monitor. The remote sensor is a diode connected transistor. This can be in the form of either a discrete NPN/PNP, such as the 2N3904/2N3906, or a diode connected PNP built into another die, such as is done on some Intel microprocessors.

The temperature of both the remote and local sensors is stored in a register that can be read via a 2-wire SMBus. The temperatures are updated at a rate that is programmable via the SMBus (the average supply current is dependent upon the update rate — the faster the rate, the higher the current).

Block diagram of NE1617A

Block diagram of NE1617A

Why Used

  • Monitors local and remote temperature
  • No calibration required
  • Programmable overtemperature/undertemperature alarm
  • 3 V to 5.5 V supply range; 5.5 V tolerant
  • Small 16-lead SSOP (QSOP) package

Where Used

  • Desktop computers
  • Notebook computers
  • Smart battery packs
  • Industrial controllers
  • Telecommunications equipment

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