Datasheet ADT7408 (Analog Devices)

±2°C Accurate, 12-Bit Digital Temperature Sensor Data Sheet ADT7408 FEATURES FUNCTIONAL BLOCK DIAGRAM V 12-bit temperature-to-digital converter DD 8 DIGITAL COMPARATOR ±2°C accuracy 12- / 10-Bit DECIMATOR – 7 EVENT# Operation from −20°C to +125°C TEMPERATURE SENSOR LPF + Operation from 3 V to 3.6 V 1-BIT CAPABILITY 240

A typical average supply current REGISTER + Selectable 1.5°C, 3°C, 6°C hysteresis CONFIGURATION – REGISTER SMBus-/I2C®-compatible interface REFERENCE ∑-∆ ALARM TEMP Dual-purpose event pin: comparator or interrupt 1-BIT UPPER DAC BOUNDARY TRIP 8-lead LFCSP, 3 mm × 3 mm (JEDEC MO-229 WEED-4) REGISTER CLK ADDRESS AND TIMING ALARM TEMP package POINTER GENERATION REGISTER LOWER BOUNDARY TRIP Complies with JEDEC standard JC-42.4 memory module REGISTER MANUFACTURER’S Thermal sensor component specification ID REGISTER CRITICAL TEMP ADT7408 REGISTER FACTORY RESERVED TEMPERATURE APPLICATIONS REGISTER REGISTER A0 1 5 SDA Memory module temperature monitoring A1 2 SMBus/I²C INTERFACE A2 6 SCL 3 Isolated sensors 4
001
Environmental control systems Vss
05716-
Computer thermal monitoring
Figure 1.
Thermal protection Industrial process control Power system monitors GENERAL DESCRIPTION
The ADT7408 is the first digital temperature sensor that complies The ADT7408 is specified for operation at supply voltages from with JEDEC standard JC-42.4 for the mobile platform memory 3.0 V to 3.6 V. Operating at 3.3 V, the average supply current is module. The ADT7408 contains a band gap temperature sensor less than 240 μA typical. The ADT7408 offers a shutdown mode and a 12-bit ADC to monitor and digitize the temperature to a that powers down the device and gives a shutdown current of 3 A resolution of 0.0625°C. typical. The ADT7408 is rated for operation over the −20°C to There is an open-drain EVENT# output that is active when the +125°C temperature range. The ADT7408 is available in a lead- monitoring temperature exceeds a critical programmable limit or free, 8-lead LFCSP, 3 mm × 3 mm (JEDEC MO-229 WEED-4) when the temperature falls above or below an alarm window. package. 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.
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS TIMING DIAGRAM ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CIRCUIT INFORMATION CONVERTER DETAILS MODES OF OPERATION REGISTERS ADDRESS POINTER REGISTER (WRITE ONLY) CAPABILITY REGISTER (READ ONLY) CONFIGURATION REGISTER (READ/WRITE) TEMPERATURE TRIP POINT REGISTERS Alarm Temperature Upper Boundary Trip Register (Read/Write) Alarm Temperature Lower Boundary Trip Register (Read/Write) Critical Temperature Trip Register (Read/Write) Temperature Value Register (Read Only) ID REGISTERS Manufacturer ID Register (Read Only) Device ID and Revision Register (Read Only) TEMPERATURE DATA FORMAT 12-Bit Temperature Data Format 10-Bit Temperature Data Format EVENT PIN FUNCTIONALITY Event Thresholds Alarm Window Trip Critical Trip Interrupt Mode Comparator Mode SERIAL INTERFACE Serial Bus Address SMBUS/I2C COMMUNICATIONS Writing Data to a Register Reading Data From the ADT7408 Writing to the Pointer Register for a Subsequent Read Reading from Any Pointer Register APPLICATIONS INFORMATION THERMAL RESPONSE TIME SELF-HEATING EFFECTS SUPPLY DECOUPLING TEMPERATURE MONITORING OUTLINE DIMENSIONS ORDERING GUIDE