Fully Released Specification
- 1 -
© Andigilog, Inc. 2006
www.andigilog.com
August 2006 - 70A05003
DIGITAL TEMPERATURE SENSOR
WITH INTEGRATED FAN CONTROL
aSC7512
PRODUCT SPECIFICATION
Product Description
The aSC7512 has a two wire digital interface compatible
with SMBus 2.0. Using a 10-bit ΣΔ- ADC, the aSC7512
measures the temperature of a remote diode connected
transistor as well as its own die.
Using temperature information from these two zones, an
automatic fan speed control algorithm is employed to
minimize acoustic impact while achieving recommended
CPU temperature under varying operational loads.
To set fan speed, the aSC7512 has a pulse width
modulation (PWM) output that is controlled by one of two
temperature zones. Both high- and low-frequency PWM
ranges are supported. The aSC7512 also includes a digital
filter that can be invoked to smooth temperature readings
for better control of fan speed and minimum acoustic
impact. The aSC7512 has a tachometer input to measure
fan speed or alternatively, an alert pin that may be
triggered by exceeding a temperature limit setting. Limit
and status registers for all measured values are included to
alert the system host that any measurements are outside of
programmed limits.
Features
•
2-wire, SMBus 2.0 compliant, serial digital
interface
•
10-bit ΣΔ-ADC
•
Monitors internal and remote thermal diodes
•
Programmable autonomous fan control based on
temperature readings
•
Noise filtering of temperature reading for fan
control
•
0.25
°C digital temperature sensor resolution
•
PWM fan speed control output for 2-, 3- or 4-wire
fans.
•
Provides high and low PWM frequency ranges
•
Fan tachometer input or ALERT output
•
8-lead MSOP or SOIC package
Measurement System
Temperature:
•
0.25°C resolution, ±1°C accuracy on remote diode
•
0.25°C resolution, ±3°C accuracy on local sensor
•
Extended temperature measurement range on
remote sensor –55°C to +125°C using or 2’s
complement coding.
Fan Tachometer:
•
16-bit count of 90KHz clock periods
Limit alarms for all measured values
Applications
•
Desktop Computers – Motherboards and Graphics
Cards
•
Laptop Computers
•
Microprocessor based equipment (e.g. Base-
stations, Routers, ATMs, Point of Sales)
Connection Diagram
Ordering Information
Part Number
Package
Temperature Range
and Operating Voltage
Marking
How Supplied
aSC7512D8
8-lead SOIC
-40°C to +125°C, 3.3V
aSC7512
Ayww
2500 units Tape & Reel
aSC7512M8
8-lead MSOP
-40°C to +125°C, 3.3V
7512
Ayww
2500 units Tape & Reel
Ayww – Assembly site, year, workweek
1
2
3
4
5
6
7
8
GND
SMBCLK
SMBDAT
VDD
D+
aSC7512
D-
PWM
TACH /
ALERT
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