ADT7475
Preliminary Technical Data
TABLE OF CONTENTS
Specifications................................ Error! Bookmark not defined.
Operating from 3.3 V Standby ................................................. 32
XNOR Tree Test Mode .............................................................. 33
Power-On Default ...................................................................... 33
Programming the Automatic Fan Speed Control Loop............ 34
Automatic Fan Control Overview............................................ 34
Step 1: Hardware Configuration ............................................. 35
Recommended Implementation 1 ........................................... 36
Recommended Implementation 2 ........................................... 37
Step 2: Configuring the MUX................................................... 38
Step 3: TMIN Settings for Thermal Calibration Channels ...... 40
Step 4: PWMMIN for Each PWM (Fan) Output ...................... 41
Step 5: PWMMAX for PWM (Fan) Outputs.............................. 41
Step 6: TRANGE for Temperature Channels................................ 42
Step 7: TTHERM for Temperature Channels ............................... 45
Absolute Maximum Ratings....... Error! Bookmark not defined.
Thermal Characteristics ......... Error! Bookmark not defined.
ESD Caution.................................................................................. 5
Pin Configuration and Function Descriptions............................. 6
Typical Performance Characteristics ............................................. 7
Product Description......................................................................... 9
Comparison between ADT7467 and ADT7475....................... 9
Recommended Implementation................................................. 9
Serial Bus Interface..................................................................... 10
Write Operations ........................................................................ 11
Read Operations......................................................................... 12
SMBus Timeout .......................................................................... 12
Voltage Measurement Input...................................................... 12
Analog-to-Digital Converter .................................................... 12
Input Circuitry............................................................................ 13
Voltage Measurement Registers................................................ 13
VCCP Limit Registers ................................................................... 13
Additional ADC Functions for Voltage Measurements ........ 13
Temperature Measurement Method ........................................ 14
Series Resistance Cancellation.................................................. 16
Factors Affecting Diode Accuracy........................................... 16
Additional ADC Functions for Temperature Measurement 18
Limits, Status Registers, and Interrupts....................................... 19
Limit Values................................................................................. 19
Status Registers ........................................................................... 20
Step 8: THYST for Temperature Channels.................................. 46
Dynamic TMIN Control Mode Error! Bookmark not defined.
Step 9: Operating Points for Temperature Channels...... Error!
Bookmark not defined.
Step 10: High and Low Limits for Temperature Channels ... 47
THERM
Step 11: Monitoring
Error! Bookmark not defined.
Enhancing System Acoustics .................................................... 48
Step 12: Ramp Rate for Acoustic Enhancement..................... 49
Register Tables ................................................................................ 53
ADT7475 Programming Block Diagram .................................... 71
Outline Dimensions....................................................................... 73
Ordering Guide .......................................................................... 73
THERM
Timer............................................................................ 22
REVISION HISTORY
Revision PrA: Initial Preliminary Version
Rev. PrC | Page 2 of 75