ADT7470 Analog Devices, Inc., ADT7470 Datasheet - Page 2

• Manufacturer Part Number: ADT7470
• Description: Temperature Sensor Hub And Fan Controller
• Manufacturer: Analog Devices, Inc.

ADT7470
TABLE OF CONTENTS
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Pin Configuration and Function Descriptions............................. 6
Functional Description .................................................................... 7
Temperature Measurement Using TMP05/TMP06 ................... 12
Temperature Reading ..................................................................... 13
Interrupt Functionality and Status Registers .............................. 14
REVISION HISTORY
7/05—Rev. A to Rev. B
References to PWM_IN changed to TMP_IN ...............Universal
Changes to T
Added Address Selection Section................................................... 7
Added Thermal Zones Section ..................................................... 12
Added Temperature Reading Section .......................................... 13
Added Note to Table 39 ................................................................. 32
Thermal Characteristics .............................................................. 5
ESD Caution.................................................................................. 5
General Description..................................................................... 7
Fan Speed Measurement.............................................................. 7
Internal Registers of the ADT7470 ............................................ 7
SMBus/I
Address Selection ......................................................................... 7
Write Operations ........................................................................ 10
Read Operations ......................................................................... 11
SMBus Timeout .......................................................................... 11
General-Purpose I/O Pins (Open Drain) ............................... 11
Measuring Temperature ............................................................ 12
TMP05/TMP06 Decoder........................................................... 12
Thermal Zones............................................................................ 12
2
C Communications Interface..................................... 7
MIN
Registers Section.................................................. 7
Rev. B | Page 2 of 40
Fan Drive Using PWM Control.................................................... 19
Fan Speed Measurement................................................................ 20
Fan Speed Control.......................................................................... 23
Registers........................................................................................... 24
Outline Dimensions ....................................................................... 39
2/05—Rev. 0 to Rev. A
Added General-Purpose I/O Pins (Open Drain) Section......... 11
11/04—Revision 0: Initial Version
Limit Values ................................................................................ 14
8-Bit Limits.................................................................................. 14
16-Bit Limits ............................................................................... 14
Out-of-Limit Comparisons....................................................... 15
Monitoring Cycle Time ............................................................. 16
Status Registers ........................................................................... 16
SMBALERT Interrupt Behavior ............................................... 17
Handling SMBALERT Interrupts............................................. 17
Masking Interrupt Sources........................................................ 18
Enabling the SMBALERT Interrupt Output........................... 18
Tach Inputs.................................................................................. 20
Fan Speed Measurement ........................................................... 20
PWM Logic State........................................................................ 23
Manual Fan Speed Control ....................................................... 23
Automatic Fan Speed Control .................................................. 23
Ordering Guide .......................................................................... 39