Current-sense amplifier with reverse-battery and load-dump protection for automotive applications

Maxim Integrated Products introduced the MAX9937, a tiny, high-side current-sense amplifier that uses external resistors to set the voltage gain for maximum design flexibility. The MAX9937 protects against accidental application of battery voltage in the reverse (wrong) direction and against inductive kickback transients and spikes (load dump) of -20V to +40V.

The MAX9937 is used in electronic control units (ECUs) to monitor current flowing inside the modules for power steering, 4-wheel drive selection, and antilock braking systems, even watching the fuse array to monitor problems.

Some of the features are listed below:

1. Features core-clamps and ESD components, along with in-circuit application components, to provide this high level of protection.
2. Voltage gain is set by the ratio of two external resistors to their accuracy.
3. Input offset voltage (VOS) is a low ±1.2mV (max).
4. Fully specified over the -40°C to +125°C automotive temperature range.
5. The MAX9937 input common-mode range is 4V to 28V and is independent of the VCC supply voltage, which can operate at 2.7V to 5.5V. When VCC is 5V, the supply current is a low 20µA. When VCC is 0V, the input bias current at the sense resistor is only 1µA to minimize battery drain when the ECU is off.

Packaging: 5-pin SC70 package
Size: 3mm x 3mm
Prices start at $0.58 (1000-up, FOB USA).
Safety features: lead- and halide-free, thereby RoHS-compliant.

For more information, go to: www.maxim-ic.com