General Description

The MAX31732 is a multi-channel temperature sensor

that monitors its own temperature and the temperatures

of up to four external diode-connected transistors. A

resistance cancellation feature compensates for up to

300Ω of series resistance between the external thermal

diode and the MAX31732, while beta compensation

corrects for temperature-measurement errors due to

low-beta sensing transistors. The sensor also allows

ideality factors between 0.9844 and 1.311.

The MAX31732 offers two open-drain, active-low

alarm outputs, ALARM1 and ALARM2. When the

measured temperature of a channel crosses the

respective primary overtemperature/undertemperature

threshold levels, ALARM1 asserts low, and a status bit

is set in the corresponding thermal status registers.

When the measured temperature of a channel crosses

the secondary overtemperature/undertemperature

threshold levels, ALARM2 asserts low and a status bit is

set in the corresponding thermal status registers. The

highest temperature register allows the controller to

obtain the temperature of the hottest channel.

A 512-bit nonvolatile memory (NVM) allows the

MAX31732 to program the configuration registers during

power-up without software/firmware intervention. The

NVM also captures the fault temperature for each

remote and local channel for further analysis at a later

time.

The 2-wire serial interface accepts SMBus protocols

(write byte, read byte, send byte, and receive byte) for

reading the temperature data and programming the

temperature thresholds. Any one of the eight available

target addresses can be selected using the address

selection input (ADD), which can be connected to

ground or connected to a grounded resistor.

The is specified over the -40°C to +125°C operating

temperature range and with a 3.0V to 3.6V input supply

range. MAX31732 is available in a 24-pin, 4mm x 4mm

TQFN package.

Features

• One Local and Four Remote Temperature-Sensing

Channels

• ±1°C Remote Temperature-Measurement Accuracy

(-40°C to +125°C)

• -64°C to +150°C Remote Temperature-

Measurement Range

• Up to 300Ω Resistance Cancellation for Remote

Channels

• Compensation for Low Beta Transistors

• 12 Bit, 0.0625°C Resolution

• Two Programmable Alarm Temperature Thresholds

• Eight Selectable Target Addresses

• Flexible I2C/SMBus Interfaces to a Variety of

Microcontrollers

• Ideality Factor of up to 1.311

• NVM Facilitates Configuration and Fault Logging

Applications

• Temperature Measurement of On-Chip CPU, ASIC,

SOC, or FPGA diodes or remote discrete diodes

• Industrial-Thermal Management