ADT7490 Datasheet, PDF (1/75 Pages) Analog Devices – dBCool Remote Thermal Monitor and Fan Controller with PECI Interface

ADT7490
dBCool^R Remote Thermal
Monitor and Fan Controller
with PECI Interface
The ADT7490 is a dBCool thermal monitor and multiple PWM fan
controller for noise−sensitive or power−sensitive applications
requiring active system cooling. The ADT7490 includes a local
temperature sensor, two remote temperature sensors including series
resistance cancellation, and monitors CPU temperature with a PECI
interface. The ADT7490 can drive a fan using either a low or high
frequency drive signal, and measure and control the speed of up to four
fans so they operate at the lowest possible speed for minimum acoustic
noise.
The automatic fan speed control loop optimizes fan speed
for a given temperature using the PECI, remote, or local temperature
information. The effectiveness of the system’s thermal solution can be
monitored using the THERM input. The ADT7490 also provides
critical thermal protection to the system using the bidirectional
THERM/SMBALERT pin as an output to prevent system or
component overheating.
Features
• Temperature Measurement
♦ 1 Local On−Chip Temperature Sensor
♦ 2 Remote Temperature Sensors
♦ 3 Current External Temperature Sensors with Series Resistance
Cancellation (SRC)
♦ PECI Interface for CPU Thermal Information and Support of Up
to 4 PECI Inputs on 1 Pin
• Fan Drive and Fan Speed Control
♦ 3 High Frequency or Low Frequency PWM Outputs for Use with
3−Wire or 4−Wire Fans
♦ 4 TACH Inputs to Measure Fan Speed
♦ OS Independent Automatic Fan Speed Control Based on Thermal
Information
♦ Dynamic T_MIN Control Mode to Optimize System Acoustics
♦ Default Startup at 100% PWM for All Fans for Robust Operation
• Bidirectional THERM/SMBALERT Pin to Flag Out−of−Limit and
Overtemperature Conditions
• GPIO Functionality to Support Extra Features
♦ Can be Used for Loadline Setting for Voltage Regulation, LED
Control, or Other Functions
• I_MON Monitoring for CPU Current and Power Information
• Footprint and Register Compatible with ADT7473/ADT7475/
ADT7476/ADT7476A Family of Fan Controllers
• SMBus Interface with Addressing Capability for Up to 3 Devices
Applications
• Personal Computers
• Servers
http://onsemi.com
QSOP−24 NB
CASE 492B
MARKING DIAGRAMS
ADT7490
ARQZ
#DateCode
1
Assembly Lot
TOP MARKING
BOTTOM MARKING
# = Pb−Free Package
PIN ASSIGNMENT
SDA 1
24 PWM1/XTO
SCL 2
GND 3
V_CC 4
GPIO1 5
GPIO2 6
PECI 7
ADT7490
TOP VIEW
23 V_CCP
22 +2.5V_IN/THERM
21 +12V_IN
20 +5V_IN
19 I_MON
18 D1+
V_TT 8
TACH3 9
17 D1–
16 D2+
PWM2/SMBALERT 10
TACH1 11
TACH2 12
15 D2–
14 ^{TACH4/THERM/SMBALERT/}
ADDR SELECT
13 PWM3/ADDREN
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 74 of this data sheet.
© Semiconductor Components Industries, LLC, 2009
1
December, 2009 − Rev. 4
Publication Order Number:
ADT7490/D