The MAX6665 is a fully integrated thermal switch with an internal power transistor for driving a cooling fan rated up to 24V and 250mA. When the MAX6665’s temperature rises above a factory-programmed threshold, the FANOUT pin becomes active and powers the fan. The MAX6665 is available with factory-programmed fan activation threshold temperatures from +40°C to +70°C in 5°C increments. Accuracy of the fan activation trip point is ±1°C (typ) and ±3°C (max). The trip point’s hysteresis is pin selectable to 1°C, 4°C, or 8°C. Two open-drain logic outputs indicate overtemperature conditions: WARN is activated when the temperature is 15°C above the fan activation threshold, and OT is activated when the temperature is 30°C above the threshold. These features can be used to safely power down systems that are overheated. The MAX6665 operates from a +2.7V to +5.5V power supply, and the associated fan can be powered from 4.5V to 24V. It is available in an 8-pin SO package and operates from -40°C to +125°C.
The MAX6665 is a fully integrated thermal switch with an internal power transistor that drives a cooling fan up to 24 V and 250 mA. It activates the fan when the die temperature exceeds a factory‑programmed threshold (40 °C‑70 °C) and provides two open‑drain over‑temperature outputs (WARN and OT).\n\nKey features include selectable hysteresis (1 °C, 4 °C, 8 °C), low supply current (65‑200 µA), and operation from a 2.7 V‑5.5 V supply. The device is supplied in an 8‑pin SO package and is rated for –40 °C to +125 °C operation, making it suitable for computers, servers, power supplies, and laboratory instruments.
| Supply Voltage (VDD) | 2.7 V – 5.5 V |
|---|---|
| Supply Current (no load) | 65 µA – 200 µA |
| FANOUT Drive Voltage | 2.6 V |
| Operating Temperature Range | -40 °C to +125 °C |
The factory‑programmed fan activation thresholds are from +40 °C to +70 °C in 5 °C steps.
The HYST pin selects hysteresis of 1 °C, 4 °C, or 8 °C by leaving it floating, connecting to GND, or to VDD respectively.
WARN activates when the temperature is 15 °C above the fan threshold; OT activates when the temperature is 30 °C above the threshold.