ASC7611 Datasheet, PDF (1/40 Pages) List of Unclassifed Manufacturers – HARDWARE MONITOR WITH INTEGRATED FAN CONTROL

Preliminary Specification
aSC7611
HARDWARE MONITOR
WITH INTEGRATED FAN CONTROL
PRODUCT SPECIFICATION
Product Description
The aSC7611 has a two wire digital interface compatible
with SMBus 2.0. Using a 10-bit ΣΔ- ADC, the aSC7611
measures the temperature of two remote diode connected
transistors as well as its own die.
Using temperature information from these three 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 aSC7611 has three independent
pulse width modulation (PWM) outputs that are controlled
by one, or a combination of three, temperature zones.
Both high- and low-frequency PWM ranges are supported.
The aSC7611 also includes a digital filter that can be
invoked to smooth temperature readings for better control
of fan speed and minimum acoustic impact. The aSC7611
has tachometer inputs to measure fan speed on up to four
fans. Limit and status registers for all measured values are
included to alert the system host that any measurements
are outside of programmed limits via status registers.
System voltages of VCCP, 2.5V, 3.3V, 5.0V, and 12V
motherboard power are monitored efficiently with internal
scaling resistors.
Measurement System
Temperature:
• 0.25°C resolution, ±2°C accuracy on remote diode
• 0.25°C resolution, ±3°C accuracy on local sensor
• Temperature measurement range on remote
sensor –55°C to +125°C using 2’s complement
coding.
Voltage:
• 10-bit Resolution, ±2% of Full Scale
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)
Features
• 2-wire, SMBus 2.0 compliant, serial interface
Connection Diagram
• 10-bit ΣΔ-ADC
• Monitors internal and remote thermal diodes
SMBDAT
1
24
• Monitors VCCP, 2.5V, 3.3V, 5.0V, and 12V
SMBCLK
motherboard/processor supplies
GND
• Programmable autonomous fan control based on
temperature readings
3.3V
• Noise filtering of temperature reading for fan
VID0
control
VID1
• 0.25°C digital temperature sensor resolution
VID2
• 3 PWM fan speed control outputs for 2-, 3- or 4-
wire fans.
VID3
2
23
3
22
4
21
5
20
6 _aSC7611 19
7
18
8
17
• Provides high and low PWM frequency ranges
TACH3
9
16
• 4 fan tachometer inputs
PWM2
10
15
• Monitors 5 VID control lines
TACH1
11
14
• 24-Lead QSOP package
• XOR-tree test mode
TACH2
12
13
PWM1/
XTESTOUT
VCCP
2.5V
12V
5V
VID4
REMOTE 1+
REMOTE 1-
REMOTE 2+
REMOTE 2-
TACH4/
AddressSelect
PWM3/
AddressEnable
Ordering Information
Part Number
Package
aSC7611QS24
24-lead QSOP
Ayww – Assembly site, year, workweek
Temperature Range
and Operating Voltage
0°C to +120°C, 3.3V
Marking
aSC7611
Ayww
How Supplied
2500 units Tape & Reel
© Andigilog, Inc. 2006
-1-
www.andigilog.com
October 2006 - 70A05007