[Andigilog, Inc.]

Product Description
The aSC7621 has a two wire digital interface compatible with SMBus 2.0. Using a 10-bit ΣΔ- ADC, the aSC7621 measures the temperature of two remote diode connected transistors as well as its own die. Support for Platform Environmental Control Interface (PECI) is included.
Using temperature information from these four 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 aSC7621 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.

FEATUREs
• Supports PECI interface and monitors internal and remote thermal diodes
• 2-wire, SMBus 2.0 compliant, serial interface
• 10-bit ΣΔ-ADC
• Monitors VCCP, 2.5V, 3.3V, 5.0V, and 12V motherboard/processor supplies
• Programmable autonomous fan control based on temperature readings
• Noise filtering of temperature reading for fan speed control
• 0.25°C digital temperature sensor resolution
• 3 PWM fan speed control outputs for 2-, 3- or 4- wire fans and up to 4 fan tachometer inputs
• Enhanced measured temperature to Temperature Zone assignment.
• Provides high and low PWM frequency ranges
• 3 GPIO pins for custom use
• 24-Lead QSOP package

APPLICATIONs
• Desktop Computers – Motherboards and Graphics Cards
• Microprocessor based equipment (e.g. Base stations, Routers, ATMs, Point of Sales)