General Description

The US90A/91A is a one-chip solution for driving two-coil brushless DC cooling fans.

Based on the advanced Melexis CMOS process, the IC contains a Hall-effect sensor, dynamic offset correction and low side output drivers.

Features and Benefits

Low cost

High sensitivity Hall Sensor

Locked rotor protection and auto-restart

Power-efficient CMOS and power MOSFETs

Built-in output protection clamping diode

Integrated tachometer (US90A) or alarm (US91A) signal output

2-coil fan driver with FG/RD output in 4-pin VK / VA and 8-pin narrow SOIC packages (all RoHS Compliant)

Application Examples

12V/24V fans

Peak current up to 500mA