adt7476a Analog Devices, Inc., adt7476a Datasheet - Page 2

• Manufacturer Part Number: adt7476a
• Description: Dbcool Remote Thermal Controller And Voltage Monitor
• Manufacturer: Analog Devices, Inc.

ADT7476A
TABLE OF CONTENTS
Features .............................................................................................. 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Pin Configuration and Function Descriptions............................. 6
Typical Performance Characteristics ............................................. 8
Product Description....................................................................... 10
REVISION HISTORY
1/06—Revision 0: Initial Version
Thermal Characteristics .............................................................. 5
ESD Caution.................................................................................. 5
Feature Comparisons Between ADT7476A and ADT7468.. 10
Recommended Implementation............................................... 10
Serial Bus Interface..................................................................... 11
Write Operations ........................................................................ 14
Read Operations ......................................................................... 14
SMBus Timeout .......................................................................... 15
Virus Protection.......................................................................... 15
Voltage Measurement Input...................................................... 15
Analog-to-Digital Converter .................................................... 15
Input Circuitry............................................................................ 15
Voltage Measurement Registers................................................ 16
Voltage Limit Registers .............................................................. 16
Extended Resolution Registers ................................................. 16
Additional ADC Functions for Voltage Measurements ........ 16
VID Code Monitoring ............................................................... 18
VID Code Input Threshold Voltage......................................... 18
VID Code Change Detect Function ........................................ 18
Programming the GPIOs........................................................... 18
Temperature Measurement Method ........................................ 18
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Limits, Status Registers, and Interrupts....................................... 23
Programming the Automatic Fan Speed Control Loop ............ 35
Register Tables ................................................................................ 51
Outline Dimensions ....................................................................... 71
Factors Affecting Diode Accuracy........................................... 20
Additional ADC Functions for Temperature Measurement 21
Limit Values ................................................................................ 23
Status Registers ........................................................................... 24
THERM Timer ........................................................................... 26
Fan Drive Using PWM Control ............................................... 29
Laying Out 3-Wire Fans ............................................................ 31
Programming T
Manual Fan Control Overview................................................. 35
THERM Operation in Manual Mode...................................... 35
Automatic Fan Control Overview............................................ 35
Step 1—Hardware Configuration ............................................ 37
Step 2—Configuring the Mux .................................................. 40
Step 3—T
Step 4—PWM
Step 5—PWM
Step 6—T
Step 7—T
Step 8—T
Fan Presence Detect................................................................... 49
Fan Sync....................................................................................... 50
Standby Mode ............................................................................. 50
XNOR Tree Test Mode .............................................................. 50
Power-On Default ...................................................................... 50
Ordering Guide .......................................................................... 71
MIN
RANGE
HYST
THERM
Settings for Thermal Calibration Channels .... 42
for Temperature Channels................................ 48
MIN
MAX
for Temperature Channels.............................. 44
for Temperature Channels ............................. 46
RANGE
for Each PWM (Fan) Output .................... 43
for PWM (Fan) Outputs............................ 43
.................................................................. 34