MAX6644 Overview
The MAX6643/MAX6644/MAX6645 monitor temperature and automatically adjust fan speed to ensure optimum cooling while minimizing acoustic noise from the fan. Each device measures two temperature locations. The MAX6643/MAX6644/MAX6645 generate a PWM waveform that drives an external power transistor, which in turn modulates the fan’s power supply.
MAX6644 Key Features
- Simple, Automatic Fan-Speed Control
- Internal and External Temperature Sensing
- Detect Fan Failure Through Locked-Rotor Output, Tachometer Output, or Fan-Supply Current Sensing
- Multiple, 1.6% Output Duty-Cycle Steps for Low Audibility of Fan-Speed Changes
- Pin-Selectable or Factory-Selectable LowTemperature Fan Threshold
- Pin-Selectable or Factory-Selectable HighTemperature Fan Threshold
- Spin-Up Time Ensures Fan Start
- Fan-Start Delay Minimizes Power-Supply Load at Power-Up
- 32Hz PWM Output
- Controlled Duty-Cycle Rate of Change Ensures Good Acoustic Performance