19-1495; Rev 1; 12/99 Remote Temperature Sensor
with SMBus Serial Interface
____________________________Features The MAX1618 precise digital thermometer reports the
temperature of a remote sensor. 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 ±3°C
for multiple transistor manufacturers, with no calibration
needed. The MAX1618 can also measure the die temperature of other ICs, such as microprocessors, that contain
an on-chip, diode-connected transistor. ♦ Single Channel: Measures Remote CPU
Temperature 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 1°C, in
two’s complement format. Measurements can be done
automatically and autonomously, with the 16Hz conversion
rate or programmed to operate in a single-shot mode. ♦ Supports SMBus Alert Response Accuracy
±3°C (+60°C to +100°C)
±5°C (-55°C to +120°C) ♦ SMBus 2-Wire Serial Interface
♦ Programmable Under/Overtemperature Alarms
♦ Overtemperature Output for Fan Control
(Thermostat Mode) † The thermostat mode configures the ALERT output as an …