Datasheet ADT7470 (Analog Devices) - 2
| Manufacturer | Analog Devices |
| Description | Temperature Sensor Hub and Fan Controller |
| Pages / Page | 40 / 2 — ADT7470. Data Sheet. TABLE OF CONTENTS. REVISION HISTORY 4/13—Rev. D to … |
| Revision | E |
| File Format / Size | PDF / 587 Kb |
| Document Language | English |
ADT7470. Data Sheet. TABLE OF CONTENTS. REVISION HISTORY 4/13—Rev. D to Rev. E. 7/05—Rev. A to Rev. B. 3/13—Rev. C to Rev. D
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ADT7470 Data Sheet TABLE OF CONTENTS
Features .. 1 Temperature Data Format ... 14 Applications ... 1 Temperature Measurement Limits ... 15 General Description ... 1 Thermal Zones for Automatic Fan Control .. 15 Functional Block Diagram .. 1 Limit and Status Registers ... 16 Revision History ... 2 Limit Values .. 16 Specifications ... 3 Temperature Limits .. 16 Serial Bus Timing Specifications .. 4 Fan Speed Limits .. 16 Absolute Maximum Ratings .. 5 Out-of-Limit Comparisons ... 16 Thermal Characteristics .. 5 Status Registers ... 17 ESD Caution .. 5 SMBALERT Interrupt .. 18 Pin Configuration and Function Descriptions ... 6 Fan Drive Using PWM Control .. 20 Functional Description .. 7 High Frequency Fan Drive .. 20 General Description ... 7 Low Frequency Fan Drive ... 20 Configuration Register 1 (Address 0x40).. 7 Setting the Fan Drive Frequency .. 21 Configuration Register 2 (Address 0x74).. 7 Inverted PWM Output .. 21 ID Registers ... 7 Fan Ful Speed Function .. 21 General-Purpose I/O Pins (Open Drain) .. 8 Fan Speed Measurement .. 22 SMBus/I2C Serial Interface .. 9 Tach Inputs .. 22 Address Selection ... 9 Fan Speed Measurement ... 23 Serial Bus Protocol ... 9 Manual Fan Speed Control ... 25 Write Operations .. 11 Setting the PWM Duty Cycle ... 25 Read Operations ... 12 Automatic Fan Speed Control .. 26 SMBus Timeout .. 12 Register Map ... 27 Temperature Measurement Using TMP05/TMP06 ... 13 Detailed Register Descriptions ... 29 Measuring Temperature .. 13 Outline Dimensions ... 39 Temperature ReadBack By the Host .. 14 Ordering Guide .. 39
REVISION HISTORY 4/13—Rev. D to Rev. E
Additions to Manual Fan Speed Control Section .. 25 Changed Input Low Voltage, V Additions to Automatic Fan Speed Control Section ... 26 IL from 0.4 V to 1.0 V and Added Test Conditions/Comments; Table 1 .. 3
7/05—Rev. A to Rev. B 3/13—Rev. C to Rev. D
References to PWM_IN changed to TMP_IN ... Universal
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
7/09—Rev. B to Rev. C 2/05—Rev. 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
11/04—Revision 0: Initial Version
Additions to Fan Drive Using PWM Control Section ... 20 Rev. E | Page 2 of 40 Document Outline Features Applications General Description Functional Block Diagram Revision History Specifications Serial Bus Timing Specifications Absolute Maximum Ratings Thermal Characteristics ESD Caution Pin Configuration and Function Descriptions Functional Description General Description ADT7470 Monitoring Cycle Configuration Register 1 (Address 0x40) Configuration Register 2 (Address 0x74) ID Registers General-Purpose I/O Pins (Open Drain) SMBus/I2C Serial Interface Address Selection Serial Bus Protocol Write Operations Send Byte Write Byte Read Operations Receive Byte Alert Response Address SMBus Timeout Temperature Measurement Using TMP05/TMP06 Measuring Temperature TMP05/TMP06 Decoder Temperature ReadBack By the Host Temperature Data Format Temperature Measurement Limits Thermal Zones for Automatic Fan Control Thermal Zone TMIN Limit and Status Registers Limit Values Temperature Limits Fan Speed Limits Out-of-Limit Comparisons Status Registers SMBALERT Interrupt Handling SMBALERT Interrupts Masking Interrupt Sources Enabling the SMBALERT Interrupt Output Fan Drive Using PWM Control High Frequency Fan Drive Low Frequency Fan Drive Setting the Fan Drive Frequency Inverted PWM Output Fan Full Speed Function Fan Speed Measurement Tach Inputs Pulse Stretching Disabling Tach measurement Fan Speed Measurement Fan Speed Measurement Registers Reading Fan Speed from the ADT7470 Fan Tach Limit Registers Fan Speed Measurement Rate Calculating Fan Speed and Tachometer Limits Fan Pulses per Revolution Manual Fan Speed Control Setting the PWM Duty Cycle Example 1: For a PWM Duty Cycle of 50% Example 2: For a PWM Duty Cycle of 33% Automatic Fan Speed Control PWM Min Duty Cycle Example: For a PWM Min Duty Cycle of 30% PWN Max Duty Cycle PWM Current Duty Cycle Register Map Detailed Register Descriptions Outline Dimensions Ordering Guide
ADT7470 Data Sheet TABLE OF CONTENTS
Features .. 1 Temperature Data Format ... 14 Applications ... 1 Temperature Measurement Limits ... 15 General Description ... 1 Thermal Zones for Automatic Fan Control .. 15 Functional Block Diagram .. 1 Limit and Status Registers ... 16 Revision History ... 2 Limit Values .. 16 Specifications ... 3 Temperature Limits .. 16 Serial Bus Timing Specifications .. 4 Fan Speed Limits .. 16 Absolute Maximum Ratings .. 5 Out-of-Limit Comparisons ... 16 Thermal Characteristics .. 5 Status Registers ... 17 ESD Caution .. 5 SMBALERT Interrupt .. 18 Pin Configuration and Function Descriptions ... 6 Fan Drive Using PWM Control .. 20 Functional Description .. 7 High Frequency Fan Drive .. 20 General Description ... 7 Low Frequency Fan Drive ... 20 Configuration Register 1 (Address 0x40).. 7 Setting the Fan Drive Frequency .. 21 Configuration Register 2 (Address 0x74).. 7 Inverted PWM Output .. 21 ID Registers ... 7 Fan Ful Speed Function .. 21 General-Purpose I/O Pins (Open Drain) .. 8 Fan Speed Measurement .. 22 SMBus/I2C Serial Interface .. 9 Tach Inputs .. 22 Address Selection ... 9 Fan Speed Measurement ... 23 Serial Bus Protocol ... 9 Manual Fan Speed Control ... 25 Write Operations .. 11 Setting the PWM Duty Cycle ... 25 Read Operations ... 12 Automatic Fan Speed Control .. 26 SMBus Timeout .. 12 Register Map ... 27 Temperature Measurement Using TMP05/TMP06 ... 13 Detailed Register Descriptions ... 29 Measuring Temperature .. 13 Outline Dimensions ... 39 Temperature ReadBack By the Host .. 14 Ordering Guide .. 39
REVISION HISTORY 4/13—Rev. D to Rev. E
Additions to Manual Fan Speed Control Section .. 25 Changed Input Low Voltage, V Additions to Automatic Fan Speed Control Section ... 26 IL from 0.4 V to 1.0 V and Added Test Conditions/Comments; Table 1 .. 3
7/05—Rev. A to Rev. B 3/13—Rev. C to Rev. D
References to PWM_IN changed to TMP_IN ... Universal
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
7/09—Rev. B to Rev. C 2/05—Rev. 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
11/04—Revision 0: Initial Version
Additions to Fan Drive Using PWM Control Section ... 20 Rev. E | Page 2 of 40 Document Outline Features Applications General Description Functional Block Diagram Revision History Specifications Serial Bus Timing Specifications Absolute Maximum Ratings Thermal Characteristics ESD Caution Pin Configuration and Function Descriptions Functional Description General Description ADT7470 Monitoring Cycle Configuration Register 1 (Address 0x40) Configuration Register 2 (Address 0x74) ID Registers General-Purpose I/O Pins (Open Drain) SMBus/I2C Serial Interface Address Selection Serial Bus Protocol Write Operations Send Byte Write Byte Read Operations Receive Byte Alert Response Address SMBus Timeout Temperature Measurement Using TMP05/TMP06 Measuring Temperature TMP05/TMP06 Decoder Temperature ReadBack By the Host Temperature Data Format Temperature Measurement Limits Thermal Zones for Automatic Fan Control Thermal Zone TMIN Limit and Status Registers Limit Values Temperature Limits Fan Speed Limits Out-of-Limit Comparisons Status Registers SMBALERT Interrupt Handling SMBALERT Interrupts Masking Interrupt Sources Enabling the SMBALERT Interrupt Output Fan Drive Using PWM Control High Frequency Fan Drive Low Frequency Fan Drive Setting the Fan Drive Frequency Inverted PWM Output Fan Full Speed Function Fan Speed Measurement Tach Inputs Pulse Stretching Disabling Tach measurement Fan Speed Measurement Fan Speed Measurement Registers Reading Fan Speed from the ADT7470 Fan Tach Limit Registers Fan Speed Measurement Rate Calculating Fan Speed and Tachometer Limits Fan Pulses per Revolution Manual Fan Speed Control Setting the PWM Duty Cycle Example 1: For a PWM Duty Cycle of 50% Example 2: For a PWM Duty Cycle of 33% Automatic Fan Speed Control PWM Min Duty Cycle Example: For a PWM Min Duty Cycle of 30% PWN Max Duty Cycle PWM Current Duty Cycle Register Map Detailed Register Descriptions Outline Dimensions Ordering Guide
