Table Of Contents - Analog Devices dBCool ADT7475 Manual

ADT7475

TABLE OF CONTENTS

Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Thermal Characteristics .............................................................. 5
ESD Caution.................................................................................. 5
Pin Configuration and Function Descriptions............................. 6
Typical Performance Characteristics ............................................. 7
Product Description......................................................................... 9
Quick Comparison Between ADT7473 and ADT7475 .......... 9
Recommended Implementation................................................. 9
Serial Bus Interface..................................................................... 10
Write Operations ........................................................................ 11
Read Operations ......................................................................... 12
SMBus Timeout .......................................................................... 12
Virus Protection.......................................................................... 12
Voltage Measurement Input...................................................... 12
Analog-to-Digital Converter .................................................... 12
Input Circuitry............................................................................ 13
Voltage Measurement Registers................................................ 13
V Limit Registers ................................................................... 13
CCP
Extended Resolution Registers ................................................. 13
Additional ADC Functions for Voltage Measurements ........ 13
Temperature Measurement Method ........................................ 15
Factors Affecting Diode Accuracy ........................................... 17
Additional ADC Functions for Temperature
Measurement............................................................................... 18
REVISION HISTORY
7/05-Revision 0: Initial Version
Limits, Status Registers, and Interrupts....................................... 20
Limit Values ................................................................................ 20
Status Registers ........................................................................... 21
THERM Timer ........................................................................... 23
Fan Drive Using PWM Control ............................................... 26
Operating from 3.3 V Standby ................................................. 31
Standby Mode ............................................................................. 31
XNOR Tree Test Mode .............................................................. 31
Power-On Default ...................................................................... 31
Programming the Automatic Fan Speed Control Loop ............ 32
Automatic Fan Control Overview............................................ 32
Step 1: Hardware Configuration .............................................. 33
Recommended Implementation 1 ........................................... 34
Recommended Implementation 2 ........................................... 35
Step 2: Configuring the Mux .................................................... 36
Step 3: T Settings for Thermal Calibration Channels ...... 38
MIN
Step 4: PWM
Step 5: PWM
Step 6: T
RANGE
Step 7: T
THERM
Step 8: T for Temperature Channels.................................. 44
HYST
Register Tables ................................................................................ 47
Outline Dimensions ....................................................................... 64
Ordering Guide .......................................................................... 64
Rev. 0 | Page 2 of 64
for Each PWM (Fan) Output ...................... 39
MIN
for PWM (Fan) Outputs.............................. 39
MAX
for Temperature Channels................................ 40
for Temperature Channels ............................... 43