ADT7476A Datasheet, PDF (1/67 Pages) Analog Devices – dBCool Remote Thermal Controller and Voltage Monitor

ADT7476A
dBCOOL^R Remote Thermal
Controller and Voltage
Monitor
The ADT7476A dBCOOL controller is a thermal monitor
and multiple PWM fan controller for noise-sensitive or
power-sensitive applications requiring active system cooling. The
ADT7476A can drive a fan using either a low or high frequency drive
signal and can monitor the temperature of up to two remote sensor
diodes plus its own internal temperature. The part also measures and
controls the speed of up to four fans, so the fans operate at the lowest
possible speed for minimum acoustic noise.
The automatic fan speed control loop optimizes fan speed
for a given temperature. The effectiveness of the system’s thermal
solution can be monitored using the THERM input. The ADT7476A
also provides critical thermal protection to the system using the
bidirectional THERM pin as an output to prevent system or
component overheating.
Features
• Monitors Up to Five Voltages
• Improved TACH and PWM Performance
• Controls and Monitors Up to Four Fans
• High and Low Frequency Fan Drive Signal
• One On-Chip and Two Remote Temperature Sensors
• Extended Temperature Measurement Range Up to 191°C
• Automatic Fan Speed Control Mode Controls System Cooling Based
on Measured Temperature
• Enhanced Acoustic Mode Dramatically Reduces User Perception of
Changing Fan Speeds
• Thermal Protection Feature via THERM Output
• Monitors Performance Impact of Intel® Pentium® 4 Processor
• Thermal Control Circuit via THERM Input
• 3-Wire and 4-Wire Fan Speed Measurement
• Limit Comparison of All Monitored Values
• 5.0 V Support on all TACH and PWM Channels
• Meets SMBus 2.0 Electrical Specifications
• These are Pb−Free Devices
http://onsemi.com
QSOP−24 NB
CASE 492B
MARKING DIAGRAMS
ADT7476AARQZ
#YYWW
xxxx
XX = Specific Device Code
#
= Pb−Free Package
YYWW = Date Code
xxxx = Assembly Lot Code
PIN ASSIGNMENT
SDA 1
24 PWM1/XTO
SCL 2
GND 3
V_CC 4
VID0/GPIO0 5
VID1/GPIO1 6
VID2/GPIO2 7
23 V_CCP
22 +2.5V_IN/THERM
21 +12V_IN/VID5
20 +5V_IN
19 VID4/GPIO4
ADT7476A
18 D1+
VID3/GPIO3 8
17 D1-
TACH3 9
PWM2/
SMBALERT
10
TACH1 11
TACH2 12
16 D2+
15 D2-
14
TACH4/THERM/SMBALERT/
GPIO6/ADDR SELECT
13 PWM3/ADDREN
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 66 of this data sheet.
© Semiconductor Components Industries, LLC, 2010
1
May, 2010 − Rev. 3
Publication Order Number:
ADT7476A/D