US79

The US79KUA is the most advanced Smart Fan Control Hall IC. It is designed for 5V and 12V cooling commutation. The chip contains many features to allow survival in a harsh environment. The IC was designed to eliminate all discrete components such as capacitors, resistors, transistors, diodes, PC board and associated labor, replacing US$0.25 to US$0.35 in direct cost.

The US79 rating guarantees proper operation up to an ambient temperature of 125°C. Hall IC circuitry and power FET output provide a low power dissipation cool chip.

Locked Rotor conditions of US79 are detected by the IC when there is no motion for one second and will shut off the motor drive for five seconds. Then, the IC US79 will turn on the drive current for one second. This sequence continues indefinitely until the locked rotor condition is fixed. This feature prevents overheating. Maximum ambient temperature is determined by driver power dissipation. For instance, at 125C ambient, driver power cannot exceed 125mW or 250mA. Future versions will offer optional features.