ADT7466
TABLE OF CONTENTS
Specifications..................................................................................... 3
Series Resistance Cancellation.................................................. 17
Temperature Measurement Method........................................ 17
Using Discrete Transistors ........................................................ 17
Temperature Measurement Using Thermistors ..................... 19
Reading Temperature from the ADT7466.............................. 20
Additional ADC Functions....................................................... 21
Limit Values ................................................................................ 21
Alert Interrupt Behavior............................................................ 23
Serial Bus Timing ......................................................................... 5
Absolute Maximum Ratings............................................................ 6
Thermal Characteristics .............................................................. 6
ESD Caution.................................................................................. 6
Pin Configuration and Function Descriptions............................. 7
Typical Performance Characteristics ............................................. 8
Functional Description.................................................................. 11
Measurement Inputs .................................................................. 11
Sequential Measurement ........................................................... 11
Fan Speed Measurement and Control ..................................... 11
Internal Registers of the ADT7466 .......................................... 11
Theory of Operation ...................................................................... 12
Serial Bus Interface..................................................................... 12
Write and Read Operations....................................................... 14
Alert Response Address (ARA)................................................ 15
SMBus Timeout .......................................................................... 15
Voltage Measurement ................................................................ 15
Reference Voltage Output.......................................................... 16
Configuration of Pin 11 and Pin 12......................................... 16
Temperature Measurement ....................................................... 17
THERM
Configuring the ADT7466
Pin as an Output......... 25
Fan Drive ..................................................................................... 26
PWM or Switch Mode Fan Drive............................................. 26
Fan Speed Measurement ........................................................... 26
Fan Start-Up Timeout................................................................ 28
Automatic Fan Speed Control .................................................. 29
Starting the Fan .......................................................................... 30
XOR Test Mode............................................................................... 31
Application Circuit......................................................................... 32
ADT7466 Register Map................................................................. 33
Register Details........................................................................... 35
Outline Dimensions....................................................................... 47
Ordering Guide .......................................................................... 47
REVISION HISTORY
6/05—Revision 0: Initial Version
Rev. 0 | Page 2 of 48