ADT7475 Analog Devices, Inc., ADT7475 Datasheet - Page 2

• Manufacturer Part Number: ADT7475
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

ADT7475
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 ............................................. 7
Product Description......................................................................... 9
Serial Bus Interface......................................................................... 10
REVISION HISTORY
11/07—Rev. A to Rev. B
Changes to Table 12........................................................................ 22
2/06—Rev. 0 to Rev. A
Changes to Table 1............................................................................ 3
Changes to Quick Comparison Between ADT7473 and
ADT7475 Section ............................................................................. 9
Changes to Analog-to-Digital Converter Section...................... 13
Changes to TACH Inputs Section ................................................ 27
Changes to Fan Speed Measurement Section ............................. 28
Timing Diagram ........................................................................... 4
Thermal Resistance ...................................................................... 5
ESD Caution.................................................................................. 5
Quick Comparison Between ADT7473 and ADT7475 .......... 9
Recommended Implementation................................................. 9
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
Extended Resolution Registers ................................................. 13
Additional ADC Functions for Voltage Measurements ........ 13
CCP
Limit Registers ................................................................... 13
Rev. B | Page 2 of 68
Limits, Status Registers, and Interrupts....................................... 20
Programming the Automatic Fan Speed Control Loop ............ 33
Register Tables ................................................................................ 48
Outline Dimensions ....................................................................... 65
Inserted Figure 42........................................................................... 32
Changes to Power-On Default Section........................................ 32
Changes to Step 5: PMW
Outputs Section .............................................................................. 40
Changes to Table 14 ....................................................................... 48
Changes to Table 23 ....................................................................... 53
Changes to Table 43 ....................................................................... 60
7/05—Revision 0: Initial Version
Temperature Measurement Method ........................................ 15
Factors Affecting Diode Accuracy........................................... 17
Additional ADC Functions for Temperature Measurement 18
Limit Values ................................................................................ 20
Interrupt 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 ...................................................................... 32
Automatic Fan Control Overview............................................ 33
Step 1: Hardware Configuration .............................................. 34
Step 2: Configuring the Mux .................................................... 37
Step 3: T
Step 4: PWM
Step 5: PWM
Step 6: T
Step 7: T
Step 8: T
Ordering Guide .......................................................................... 65
MIN
RANGE
THERM
HYST
Settings for Thermal Calibration Channels ...... 39
for Temperature Channels.................................. 45
MIN
MAX
for Temperature Channels................................ 41
for Temperature Channels ............................... 44
for Each PWM (Fan) Output ...................... 40
for PWM (Fan) Outputs.............................. 40
MAX
For PWM (Fan)