REV. A
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ADM1027
*
dBCOOL
™
Remote Thermal
Controller and Voltage Monitor
*Protected by U.S. Patent Nos. 6,188,189; 6,169,442; 6,097,239; 5,982,221;
and 5,867,012. Other patents pending.
FEATURES
Monitors up to 5 Supply Voltages
Controls and Monitors up to 4 Fan Speeds
1 On-Chip and 2 Remote Temperature Sensors
Monitors up to 5 Processor VID Bits
Automatic Fan Speed Control Mode Controls System
Cooling Based on Measured Temperature
Enhanced Acoustic Mode Dramatically Reduces User
Perception of Changing Fan Speeds
2-Wire and 3-Wire Fan Speed Measurement
Limit Comparison of All Monitored Values
Meets SMBus 2.0 Electrical Specifications
(Fully SMBus 1.1 Compliant)
APPLICATIONS
Low Acoustic Noise PCs
Networking and Telecommunications Equipment
FUNCTIONAL BLOCK DIAGRAM
GENERAL DESCRIPTION
The ADM1027 dBCOOL controller is a complete systems
monitor and multiple PWM fan controller for noise sensitive
applications requiring active system cooling. It can monitor
12 V, 5 V, 2.5 V CPU supply voltage, plus its own supply volt-
age. It can monitor the temperature of up to two remote sensor
diodes, plus its own internal temperature. It can measure and
control the speed of up to four fans so that they operate at the
lowest possible speed for minimum acoustic noise. The auto-
matic fan speed control loop optimizes fan speed for a given
temperature. Once the control loop parameters are programmed,
the ADM1027 can vary fan speed without CPU intervention.
BAND GAP
REFERENCE
10-BIT
ADC
INPUT
SIGNAL
CONDITIONING
AND
ANALOG
MULTIPLEXER
GND
SERIAL BUS
INTERFACE
SCL SDA
VID
REGISTER
FAN SPEED
COUNTER
ADDRESS
POINTER
REGISTER
ADM1027
VALUE AND
LIMIT
REGISTERS
LIMIT
COMPARATORS
PWM
CONFIGURATION
REGISTERS
INTERRUPT
STATUS
REGISTERS
BAND GAP
TEMP. SENSOR
VID4
VID3
VID2
VID1
VID0
PWM
REGISTERS
AND
CONTROLLERS
PWM1
PWM2
V
CC
TO ADM1027
AUTOMATIC
FAN SPEED
CONTROL
PWM3
TACH1
TACH2
TACH3
TACH4
INTERRUPT
MASKING
SMBALERT
ACOUSTIC
ENHANCEMENT
CONTROL
V
CC
D1+
D1–
D2+
D2–
+5V
IN
+12V
IN
+2.5V
IN
V
CCP
SMBUS
ADDRESS
SELECTION
ADDR EN
ADDR
SELECT