The NE1617 is an accurate two-channel temperature monitor. It measures the temperature of itself and the temperature of a remote sensor. 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).
In addition to the normal operation, which is to update the temperature at the programmed rate, there is a one shot mode that will force a temperature update. There is also an alarm that senses either an over or under temperature condition. The trip points for this alarm are also
programmable. The device can have 1 of 9 addresses (determined by 2 address pins), so there can be up to 9 of the NE1617 on the SMBus.
It can also be put in a standby mode (in order to save power). This can be done either with software (over the SMBus) or with hardware (using the STANDBY pin). The NE1617 is a replacement for Maxim MAX1617 and Analog Devices ADM1021.