ADT7475_1110 ONSEMI [ON Semiconductor], ADT7475_1110 Datasheet - Page 28

• Manufacturer Part Number: ADT7475_1110
• Description: dbCOOL Remote Thermal Monitor and Fan Controller
• Manufacturer: ONSEMI [ON Semiconductor]

Step 1: Hardware Configuration
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:
During system design, the motherboard sensing and
1. What ADT7475 functionality will be used?
2. How many fans will be supported in the system,
•
•
three or four? This influences the choice of
PWM2 or SMBALERT?
TACH4 fan speed measurement or
overtemperature THERM function?
The ADT7475 offers multifunctional pins that
can be reconfigured to suit different system
requirements and physical layouts. These
multifunction pins are software programmable.
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
Figure 43. Hardware Configuration Example
RANGE
RANGE
RANGE
100%
100%
100%
0%
0%
0%
MUX
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PWM
PWM
PWM
MIN
MIN
MIN
CONFIG
CONFIG
CONFIG
TACHOMETER 1
MEASUREMENT
TACHOMETER 2
MEASUREMENT
TACHOMETER 3
MEASUREMENT
PWM
PWM
PWM
3. s the CPU fan to be controlled using the ADT7475
4. Where will the ADT7475 be physically located in
GENERATOR
GENERATOR
GENERATOR
whether to use the TACH4 pin or to reconfigure it
for the THERM function.
or will it run at full speed 100% of the time?
If run at 100%, this frees up a PWM output, but
the system is louder.
the system?
This influences the assignment of the temperature
measurement channels to particular system
thermal zones. For example, locating the
ADT7475 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