ADT7470_15 Datasheet, PDF (1/40 Pages) Analog Devices – Temperature Sensor Hub and Fan Controller

Data Sheet
Temperature Sensor Hub and Fan Controller
ADT7470
FEATURES
Monitors up to 10 remote temperature sensors
Monitors and controls speed of up to 4 fans independently
PWM outputs drive each fan under software control
FULL_SPEED input allows fans to be blasted to maximum
speed by external hardware
SMBALERT interrupt signals failures to system controller
Three-state ADDR pin allows up to 3 devices on a single bus
Temperature decoder interprets TMP05 temperature sensors
and communicates values over I²C bus
Limit comparison of all monitored values
Supports fast I²C standard (400 kHz max)
Meets SMBus 2.0 electrical specifications
(fully SMBus 1.1-compliant)
APPLICATIONS
Servers
Networking and telecommunications equipment
Desktops
GENERAL DESCRIPTION
The ADT7470¹ controller is a multichannel temperature sensor
and PWM fan controller and fan speed monitor for systems
requiring active cooling. It is designed to interface directly to
an I²C® bus. The ADT7470 can monitor up to 10 daisy-chained
TMP05 temperature sensors. It can also monitor and control
the speed of four fans, in automatic or in manual control loops.
A FULL_SPEED input is provided to allow the fans to be
blasted to maximum speed, via external hardware control,
under extreme thermal conditions or on system startup. An
SMBALERT interrupt communicates error conditions such as
fan under speed and over temperature measurements to the
system service processor. Individual error conditions can then
be read from status registers over the I²C bus.
FUNCTIONAL BLOCK DIAGRAM
ADDR
SDA SCL SMBALERT
ADT7470
FULL_SPEED
SMBus
ADDRESS
SELECTION
SERIAL BUS
INTERFACE
ADDRESS
POINTER
REGISTER
PWM1
PWM2
PWM3
PWM4
TACH1
TACH2
TACH3
TACH4
TMP_START
TMP_IN
PWM
REGISTERS
AND
CONTROLLERS
AUTOMATIC
FAN SPEED
CONTROL
FAN SPEED
COUNTERS
TEMPERATURE
DECODER
PWM
CONFIG
REGISTERS
INTERRUPT
MASKING
INTERRUPT
STATUS
REGISTERS
LIMIT
COMPARATORS
VALUE AND
LIMIT
REGISTERS
Figure 1.
1 _{Protected by Patent Numbers US6,169,442, US6,097,239, US5,982,221, US5,867,012. Other patents pending.}
Rev. E
Document Feedback
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] ©2004–2013 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com