
The MAX1617 is a precise digital
thermometer that reports the temperature of both a
remote sensor and its own package. The remote sensor
is a diode-connected transistor - typically a low-cost,
easily mounted 2N3904 NPN type - that replaces conventional
thermistors or thermocouples. Remote accuracy
is +-3C for multiple transistor manufacturers, with
no calibration needed. The remote channel can also
measure the die temperature of other ICs, such as
microprocessors, that contain an on-chip, diode-connected
transistor.
The 2-wire serial interface accepts standard System
Management Bus (SMBus) Write Byte, Read Byte,
Send Byte, and Receive Byte commands to program the
alarm thresholds and to read temperature data. The data
format is 7 bits plus sign, with each bit corresponding to
1C, in twos-complement format. Measurements can be
done automatically and autonomously, with the conversion
rate programmed by the user or programmed to
operate in a single-shot mode. The adjustable rate allows
the user to control the supply-current drain.
The MAX1617 is available in a small, 16-pin QSOP surface-
mount package.