adt7476a Analog Devices, Inc., adt7476a Datasheet - Page 37

• Manufacturer Part Number: adt7476a
• Description: Dbcool Remote Thermal Controller And Voltage Monitor
• Manufacturer: Analog Devices, Inc.

STEP 1—HARDWARE CONFIGURATION
During system design, the motherboard sensing and control
capabilities should be addressed early in the design stages.
Decisions about how these capabilities are used should involve the
system thermal/mechanical engineer. Ask the following questions:
1.
What ADT7476A functionality is used?
•
•
•
•
The ADT7476A offers multifunctional pins that can be
reconfigured to suit different system requirements and
physical layouts. These multifunction pins are software
programmable.
PWM2 or SMBALERT ?
TACH4 fan speed measurement or overtemperature
THERM function?
2.5 V voltage monitoring or overtemperature THERM
function?
12 V voltage monitoring or VID5 input?
AMBIENT TEMP
REMOTE 1 =
REMOTE 2 =
VRM TEMP
CPU TEMP
LOCAL =
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
T
T
T
MIN
MIN
MIN
T
T
T
RANGE
RANGE
RANGE
100%
100%
100%
0%
0%
0%
Figure 48. Hardware Configuration Example
MUX
Rev. 0 | Page 37 of 72
PWM
PWM
PWM
MIN
MIN
MIN
2.
3.
4.
CONFIG
CONFIG
CONFIG
TACHOMETER 1
MEASUREMENT
TACHOMETER 2
MEASUREMENT
TACHOMETER 3
MEASUREMENT
PWM
PWM
PWM
GENERATOR
GENERATOR
GENERATOR
How many fans are supported in system, three or four?
This influences the choice of whether to use the
TACH4 pin or to reconfigure it for the THERM function.
Is the CPU fan to be controlled using the ADT7476A, or
will the CPU fan run at full speed 100% of the time?
If run at 100%, this frees up a PWM output, but the system
is louder.
Where will the ADT7476A be physically located in the
system?
This influences the assignment of the temperature meas-
urement channels to particular system thermal zones. For
example, locating the ADT7476A close to the VRM
controller circuitry allows the VRM temperature to be
monitored using the local temperature channel.
AND 4
PWM
PWM
PWM
ENHANCEMENT)
ENHANCEMENT)
ENHANCEMENT)
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
CONTROL
CONTROL
CONTROL
RAMP
RAMP
RAMP
PWM1
TACH1
PWM2
TACH2
PWM3
TACH3
FRONT CHASSIS
REAR CHASSIS
CPU FAN SINK
ADT7476A