ADT7468 Datasheet, PDF (1/80 Pages) Analog Devices – dBCool™ Remote Thermal Controller and Voltage Monitor

dBCool^™ Remote Thermal
Controller and Voltage Monitor
ADT7468
FEATURES
GENERAL DESCRIPTION
Monitors up to 5 voltages
Controls and monitors up to 4 fans
High and low frequency fan drive signal
1 on-chip and 2 remote temperature sensors
Series resistance cancellation on the remote channel
Extended temperature measurement range, up to 191°C
Dynamic TMIN control mode optimizes system acoustics
intelligently
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
2-wire, 3-wire, and 4-wire fan speed measurement
Limit comparison of all monitored values
Meets SMBus 2.0 electrical specifications
(fully SMBus 1.1 compliant)
The ADT7468 dBCOOL^TM controller is a thermal monitor and
multiple PWM fan controller for noise-sensitive or power-
sensitive applications requiring active system cooling. The
ADT7468 can drive a fan using either a low or high frequency
drive signal, monitor the temperature of up to two remote
sensor diodes plus its own internal temperature, and measure
and control the speed of up to four fans, so that they operate at
the lowest possible speed for minimum acoustic noise.
The automatic fan speed control loop optimizes fan speed for a
given temperature. A unique dynamic TMIN control mode
enables the system thermals/acoustics to be intelligently
managed. The effectiveness of the system’s thermal solution can
be monitored using the THERM input. The ADT7468 also
provides critical thermal protection to the system using the
bidirectional THERM pin as an output to prevent system or
component overheating.
FUNCTIONAL BLOCK DIAGRAM
VID5
VID4
VID3
VID2
VID1
VID0
PWM1
PWM2
PWM3
TACH1
TACH2
TACH3
TACH4
PWM REGISTERS
AND
CONTROLLERS
HF & LF
ACOUSTIC
ENHANCEMENT
CONTROL
ACOUSTIC
ENHANCEMENT
CONTROL
FAN SPEED
COUNTER
PERFORMANCE
MONITORING
SCL SDA SMBALERT
SERIAL BUS
INTERFACE
AUTOMATIC
FAN SPEED
CONTROL
DYNAMIC
T_MIN
CONTROL
ADDRESS
POINTER
REGISTER
PWM
CONFIGURATION
REGISTERS
INTERRUPT
MASKING
THERM
V_CC
D1+
D1–
D2+
D2–
+5V_IN
+12V_IN
+2.5V_IN
V_CCP
V_CC TO ADT7468
SRC
THERMAL
PROTECTION
INPUT
SIGNAL
CONDITIONING
AND
ANALOG
MULTIPLEXER
ADT7468
10-BIT
ADC
BAND GAP
REFERENCE
INTERRUPT
STATUS
REGISTERS
LIMIT
COMPARATORS
VALUE AND
LIMIT
REGISTERS
BAND GAP
TEMP SENSOR
GND
Figure 1.
Rev. 0
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