MAX6643 Datasheet | Maxim Integrated

19-3305; Rev 0; 5/04 Automatic PWM Fan-Speed Controllers with Overtemperature Output General Description 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. The MAX6643/MAX6644/MAX6645 monitor temperature and adjust the duty cycle of the PWM output waveform to control the fan’s speed according to the cooling needs of the system. The MAX6643 monitors its own die temperature and an optional external...