Temperature Sensor Hub and Fan Controller Data Sheet ADT7470 FEATURES GENERAL DESCRIPTION 1 Monitors up to 10 remote temperature sensors The ADT7470 controller is a multichannel temperature sensor Monitors and controls speed of up to 4 fans independently and PWM fan controller and fan speed monitor for systems PWM outputs drive each fan under software control requiring active cooling. It is designed to interface directly to FULL SPEED 2 input allows fans to be blasted to maximum an I C bus. The ADT7470 can monitor up to 10 daisy-chained speed by external hardware TMP05 temperature sensors. It can also monitor and control SMBALERT interrupt signals failures to system controller the speed of four fans, in automatic or in manual control loops. Three-state ADDR pin allows up to 3 devices on a single bus FULL SPEED A input is provided to allow the fans to be Temperature decoder interprets TMP05 temperature sensors 2 and communicates values over I C bus blasted to maximum speed, via external hardware control, Limit comparison of all monitored values under extreme thermal conditions or on system startup. An 2 Supports fast I C standard (400 kHz max) SMBALERT interrupt communicates error conditions such as Meets SMBus 2.0 electrical specifications fan under speed and over temperature measurements to the (fully SMBus 1.1-compliant) system service processor. Individual error conditions can then 2 be read from status registers over the I C bus. APPLICATIONS Servers Networking and telecommunications equipment Desktops FUNCTIONAL BLOCK DIAGRAM SMBALERT ADDR SDA SCL ADT7470 SMBus SERIAL BUS ADDRESS INTERFACE FULL SPEED ADDRESS SELECTION POINTER REGISTER PWM1 PWM AUTOMATIC PWM PWM2 REGISTERS FAN SPEED CONFIG AND CONTROL PWM3 REGISTERS CONTROLLERS PWM4 INTERRUPT TACH1 MASKING TACH2 FAN SPEED COUNTERS TACH3 INTERRUPT TACH4 STATUS REGISTERS TMP START LIMIT TEMPERATURE COMPARATORS DECODER TMP IN VALUE AND LIMIT REGISTERS Figure 1. 1 Protected by Patent Numbers US6,169,442, US6,097,239, US5,982,221, US5,867,012. Other patents pending. Rev. E Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. 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Technical Support www.analog.com 04684-0-001ADT7470 Data Sheet TABLE OF CONTENTS Temperature Data Format ......................................................... 14 Features .............................................................................................. 1 Temperature Measurement Limits ........................................... 15 Applications ....................................................................................... 1 Thermal Zones for Automatic Fan Control ............................ 15 General Description ......................................................................... 1 Limit and Status Registers ............................................................. 16 Functional Block Diagram .............................................................. 1 Limit Values ................................................................................ 16 Revision History ............................................................................... 2 Temperature Limits .................................................................... 16 Specifications ..................................................................................... 3 Fan Speed Limits ........................................................................ 16 Serial Bus Timing Specifications ................................................ 4 Out-of-Limit Comparisons ....................................................... 16 Absolute Maximum Ratings ............................................................ 5 Status Registers ........................................................................... 17 Thermal Characteristics .............................................................. 5 SMBALERT Interrupt ................................................................ 18 ESD Caution .................................................................................. 5 Fan Drive Using PWM Control .................................................... 20 Pin Configuration and Function Descriptions ............................. 6 High Frequency Fan Drive ........................................................ 20 Functional Description .................................................................... 7 Low Frequency Fan Drive ......................................................... 20 General Description ..................................................................... 7 Setting the Fan Drive Frequency .............................................. 21 Configuration Register 1 (Address 0x40).................................. 7 Inverted PWM Output .............................................................. 21 Configuration Register 2 (Address 0x74).................................. 7 Fan Full Speed Function ............................................................ 21 ID Registers ................................................................................... 7 Fan Speed Measurement ................................................................ 22 General-Purpose I/O Pins (Open Drain) ...................................... 8 2 Tach Inputs .................................................................................. 22 SMBus/I C Serial Interface .............................................................. 9 Fan Speed Measurement ........................................................... 23 Address Selection ......................................................................... 9 Manual Fan Speed Control ........................................................... 25 Serial Bus Protocol ....................................................................... 9 Setting the PWM Duty Cycle ................................................... 25 Write Operations ........................................................................ 11 Automatic Fan Speed Control ...................................................... 26 Read Operations ......................................................................... 12 Register Map ................................................................................... 27 SMBus Timeout .......................................................................... 12 Detailed Register Descriptions ..................................................... 29 Temperature Measurement Using TMP05/TMP06 ................... 13 Outline Dimensions ....................................................................... 39 Measuring Temperature ............................................................ 13 Ordering Guide .......................................................................... 39 Temperature ReadBack By the Host ........................................ 14 REVISION HISTORY 4/13Rev. D to Rev. E Additions to Manual Fan Speed Control Section ...................... 25 Additions to Automatic Fan Speed Control Section ................. 26 Changed Input Low Voltage, V from 0.4 V to 1.0 V and Added IL Test Conditions/Comments Table 1 .............................................. 3 7/05Rev. A to Rev. B References to PWM IN changed to TMP IN ............... Universal 3/13Rev. C to Rev. D Changes to TMIN Registers Section .................................................. 7 Changes to Calculating Fan Speed and Tachometer Limits Added Address Selection Section .................................................... 7 Section .............................................................................................. 24 Added Thermal Zones Section ..................................................... 12 Changes to Bit 3, Table 43.............................................................. 35 Added Temperature Reading Section .......................................... 13 Updated Outline Dimensions ....................................................... 39 Added Note to Table 39 ................................................................. 32 7/09Rev. B to Rev. C 2/05Rev. 0 to Rev. A Changes to Functional Description Section ................................. 7 Added General-Purpose I/O Pins (Open Drain) Section ......... 11 Added Temperature Data Format Section .................................. 14 11/04Revision 0: Initial Version Additions to Fan Drive Using PWM Control Section ............... 20 Rev. E Page 2 of 40