The MAX9921 is a Hall effect sensor power supply and interface chip produced by TI. The chip can provide current, monitor current, filter current and output logic level. In addition, the chip also has fault diagnosis and protection functions, which can detect open inputs, inputs shorted to the battery, and inputs shorted to ground.
The MAX9921 provides a single‑chip solution for interfacing two 2‑wire Hall‑effect sensors to a low‑voltage micro‑processor. It supplies and monitors sensor current, filters the sensed level, and outputs a corresponding logic level while offering input diagnostics and fault protection such as open‑input and short‑to‑ground detection.
The device operates from 6 V to 18 V, tolerates up to 60 V transients, and is available in a 10‑pin uMAX package rated for automotive temperature ranges (‑40 °C to +125 °C). Typical applications include door modules, window lifters, seat movers, and other automotive control systems.
| Operating Voltage Range | 6 V to 18 V |
|---|---|
| Temperature Range | -40 °C to +125 °C |
| Maximum Supply Voltage | 60 V |
| Blanking Time after Power‑up | 80 µs |
| Input Voltage High (DIAG, OE) | 21 V |
| Package Type | 10‑pin uMAX |
The device can withstand up to 60 V at the battery supply and Hall inputs.
It can interface two 2‑wire Hall‑effect sensors.
The blanking time is 80 µs.
It is offered in a 10‑pin uMAX package.