ADT7468 Analog Devices, Inc., ADT7468 Datasheet - Page 2

• Manufacturer Part Number: ADT7468
• Description: Dbcool Remote Thermal Controller And Voltage Monitor
• Manufacturer: Analog Devices, Inc.

ADT7468
TABLE OF CONTENTS
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Pin Configuration and Function Descriptions............................. 6
Typical Performance Characteristics ............................................. 8
Product Description....................................................................... 10
Serial Bus Interface......................................................................... 12
VID Code Monitoring ................................................................... 15
Analog-to-Digital Converter ........................................................ 16
Limits, Status Registers, and Interrupts....................................... 22
Active Cooling ................................................................................ 28
REVISION HISTORY
7/05—Rev. 0 to Rev. A
Changes to Absolute Maximum Ratings ................................... 5
Changes to Table 17.................................................................... 62
ESD Caution.................................................................................. 5
Comparison between ADT7463 and ADT7468..................... 10
Recommended Implementation............................................... 11
Write Operations ........................................................................ 13
Read Operations ......................................................................... 14
SMBus Timeout .......................................................................... 14
VID Code Registers.................................................................... 15
Voltage Measurement Input...................................................... 16
Additional ADC Functions for Voltage Measurements ........ 16
Temperature Measurement ....................................................... 18
Additional ADC Functions for
Temperature Measurement ....................................................... 21
Limit Values................................................................................. 22
Status Registers ........................................................................... 23
Interrupts..................................................................................... 23
Driving the Fan Using PWM Control ..................................... 28
Laying Out 2-Wire and 3-Wire Fans ....................................... 30
Fan Speed Measurement............................................................ 31
Fan Spin-Up ................................................................................ 33
Rev. A | Page 2 of 84
Miscellaneous Functions ............................................................... 35
Automatic Fan Control Overview................................................ 37
Programming the Automatic Fan Speed Control Loop ............ 40
Enhancing System Acoustics ........................................................ 60
Register Tables ................................................................................ 62
ADT7468 Programming Block Diagram .................................... 81
Outline Dimensions ....................................................................... 82
Changes to Ordering Guide ...................................................... 80
4/04—Revision 0: Initial Version
PWM Logic State........................................................................ 34
Fan Speed Control...................................................................... 34
Operating from 3.3 V Standby ................................................. 35
XNOR Tree Test Mode .............................................................. 35
Power-On Default ...................................................................... 35
Dynamic T
Step 1: Hardware Configuration .............................................. 40
Step 2: Configuring the Mux .................................................... 43
Step 3: T
Step 4: PWM
Step 5: PWM
Step 6: T
Step 7: T
Step 8: T
Step 9: Operating Points for Temperature Channels............. 52
Step 10: High and Low Limits for Temperature Channels ... 53
Step 11: Monitoring THERM ................................................... 56
Step 12: Ramp Rate for Acoustic Enhancement..................... 57
Acoustic Enhancement Mode Overview ................................ 60
Ordering Guide .......................................................................... 82
MIN
RANGE
THERM
HYST
MIN
Settings for Thermal Calibration Channels ...... 45
for Temperature Channels.................................. 51
MIN
MAX
for Temperature Channels................................ 47
for Temperature Channels ............................... 50
Control Mode ................................................... 38
for Each PWM (Fan) Output ...................... 46
for PWM (Fan) Outputs.............................. 46