US91A Datasheet | Melexis

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 Ro HS pliant) Application Examples 12V/24V fans Peak current up to 500m A Ordering Information .. Part No. US90A US90A US90A US91A US91A US91A Temperature Code E (-40° C to 85° C) E (-40° C to 85° C) E (-40° C to 85° C) E (-40° C to 85° C) E (-40° C to 85° C) E (-40° C to 85° C) Package Code VK (4-pin TO-92) DC (8-pin narrow SOIC) VA (4-pin TO-92 flat) VK (4-pin TO-92) DC (8-pin narrow SOIC) VA (4-pin TO-92 flat) 1 Functional Diagram 2 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. Frequency Generator or Rotation Detection is available. The open-drain output makes the connectivity with any external interface such as hardware monitoring or Super I/O IC easier. These features are bined with the Melexis patented no-VDD design to fit the IC in small 4-pin VK and VA package. The device is also delivered in DC package for automatic assembly. 390109026302 Rev 002 Page 1 of 12 Data Sheet Apr/07 US90A / US91A 24V Hall IC Fan Driver Table of Contents 1 Functional Diagram 1 2 General Description 1 3 Glossary of Terms 3 4 Absolute Maximum Ratings 3 5...