1. General description
The NE1617A 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 overtemperature or undertemperature
condition. The trip points for this alarm are also programmable.
The device can have one of nine addresses (determined by two address pins), so there
can be up to nine of the NE1617A on the SMBus.
It can also be put in standby mode (in order to save power). This can be done either with
software (over the SMBus) or with hardware (using the STBY
pin).
2. Features and benefits
Replacement for Maxim MAX1617 and Analog Devices ADM1021
Monitors local and remote temperature
Local (on-chip) sensor accuracy:
2 C at 60 C to 100 C
3 C at 40 C to 125 C
Remote sensor accuracy:
3 C at 60 C to 100 C
5 C at 40 C to 125 C
No calibration required
Programmable overtemperature/undertemperature alarm
SMBus 2-wire serial interface up to 100 kHz
3 V to 5.5 V supply range; 5.5 V tolerant
70 A supply current in operating mode
3 A (typical) supply current in standby mode
NE1617A
Temperature monitor for microprocessor systems
Rev. 5 — 20 March 2012 Product data sheet
