ADT7475 View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
ADT7475 Datasheet PDF : 68 Pages
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PRODUCT DESCRIPTION
The ADT7475 is a complete thermal monitor and multiple fan
controller for any system requiring thermal monitoring and
cooling. The device communicates with the system via a serial
system management bus. The serial bus controller has a serial
data line for reading and writing addresses and data (Pin 16),
and an input line for the serial clock (Pin 1). All control and
programming functions for the ADT7475 are performed over
the serial bus. In addition, a pin can be reconfigured as an
SMBALERT output to signal out-of-limit conditions.
QUICK COMPARISON BETWEEN ADT7473 AND
ADT7475
• The ADT7473 supports Advanced Dynamic TMIN features
while the ADT7475 does not.
• Acoustic smoothing is improved on the ADT7475.
• THERM can be selected as an output only on the
ADT7475.
• The ADT7475 has two additional configuration registers.
• The ADT7475 has other minor register changes.
• The ADT7475 is similar to the ADT7473 in that it is
powered by a supply no greater than 3.6 V. Exceeding this
specification results in irreversible damage to the
ADT7475. Signal pins (TACH/PWM) should be pulled up
or clamped to 3.6 V maximum. See the Specifications
section for more information.
ADT7475
RECOMMENDED IMPLEMENTATION
Configuring the ADT7475 as shown in Figure 13 allows the
system designer to use the following features:
• Two PWM outputs for fan control of up to three fans
(the front and rear chassis fans are connected in parallel).
• Three TACH fan speed measurement inputs.
• VCC measured internally through Pin 3.
• CPU temperature measured using Remote 1 temperature
channel.
• Ambient temperature measured through Remote 2
temperature channel.
• Bidirectional THERM pin. This feature allows Intel
Pentium 4 PROCHOT monitoring and can function as
an overtemperature THERM output. The THERM pin
can alternatively be programmed as an SMBALERT system
interrupt output.
FRONT
CHASSIS
FAN
REAR
CHASSIS
FAN
AMBIENT
TEMPERATURE
ADT7475
TACH2
PWM1
TACH1
CPU FAN
PWM3
TACH3
D2+
D2–
THERM
D1+
SDA
D1–
SCL
SMBALERT
GND
PROCHOT
ICH
CPU
Figure 13. ADT7475 Configuration
Rev. A | Page 9 of 68
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