±2°C Accurate, 12-Bit Digital

Temperature Sensor

ADT7408

Rev. 0

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FEATURES

12-bit temperature-to-digital converter

±2°C accuracy

Operation from −20°C to +125°C

Operation from 3 V to 3.6 V

240

μA typical average supply current

Selectable 1.5°C, 3°C, 6°C hysteresis

Dual-purpose event pin: comparator or interrupt

8-lead LFCSP_VD, 3 mm × 3 mm (JEDEC MO-229 VEED-4)

package

Complies with JEDEC standard JC-42.4 memory module

Thermal sensor component specification

APPLICATIONS

Memory module temperature monitoring

Isolated sensors

Environmental control systems

Computer thermal monitoring

Thermal protection

Industrial process control

Power system monitors

FUNCTIONAL BLOCK DIAGRAM

12- / 10-Bit

ADDRESS

POINTER

REGISTER

EVENT#

∑-∆

DIGITAL COMPARATOR

DECIMATOR

A1

A0

A2

SMBus/I²C INTERFACE

ADT7408

SDA

SCL

FACTORY

RESERVED

REGISTER

TEMPERATURE

REGISTER

MANUFACTURER’S

ID REGISTER

CRITICAL TEMP

REGISTER

ALARM TEMP

LOWER

BOUNDARY TRIP

REGISTER

ALARM TEMP

UPPER

BOUNDARY TRIP

REGISTER

CONFIGURATION

REGISTER

CAPABILITY

REGISTER

REFERENCE

TEMPERATURE

SENSOR

CLK

AND TIMING

GENERATION

1-BIT

6

5

4

1

2

3

7

8

+

–

LPF

1-BIT

DAC

+

–

Figure 1.

GENERAL DESCRIPTION

The ADT7408 is the first digital temperature sensor that complies

with JEDEC standard JC-42.4 for the mobile platform memory

module. The ADT7408 contains a band gap temperature sensor

and a 12-bit ADC to monitor and digitize the temperature to a

resolution of 0.0625°C.

There is an open-drain EVENT# output that is active when the

monitoring temperature exceeds a critical programmable limit or

when the temperature falls above or below an alarm window.

This pin can operate in either comparator or interrupt mode.

There are three slave device address pins that allow up to eight

ADT7408s to be used in a system that monitors temperature of

various components and subsystems.

The ADT7408 is specified for operation at supply voltages from

3.0 V to 3.6 V. Operating at 3.3 V, the average supply current is

less than 240 μA typical. The ADT7408 offers a shutdown mode

that powers down the device and gives a shutdown current of 3 μA

typical. The ADT7408 is rated for operation over the −20°C to

+125°C temperature range. The ADT7408 is available in a lead-

free, 8-lead LFCSP_VD, 3 mm × 3 mm (JEDEC MO-229 VEED-4)

package.