ADT7475 datasheet(9/68 Pages) AD

9 / 68 page

ADT7475

Rev. A | Page 9 of 68

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

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.

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.

TACH2

PWM3

TACH3

D1+

D1–

GND

ADT7475

SCL

SDA

TACH1

PWM1

CPU FAN

AMBIENT

TEMPERATURE

SMBALERT

D2+

D2–

THERM

PROCHOT

FRONT

CHASSIS

FAN

REAR

CHASSIS

FAN

CPU

ICH

Figure 13. ADT7475 Configuration

ADT7475 Datasheet(PDF) 9 Page - Analog Devices

ADT7475 Datasheet(HTML) 9 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

Datasheet Download

Link URL