Auto Electronics

Overvoltage Protection Circuits Operate up to 72 V

The MAX6495-MAX6499 series of overvoltage protection circuits from Maxim Integrated Products operates as a switch controller to either disconnect or limit the output voltage to a load during an overvoltage condition. The circuits turn off an external n-channel MOSFET with an internal 100 mA pulldown current when the monitored voltage exceeds its overvoltage threshold. These low-power devices consume only 20 microamps of quiescent current and operate from 5.5 V to 72 V, making them suitable for automotive, industrial and server applications.

The MAX6497 features a latch-off mode that disables the MOSFET until the power or shutdown input is cycled. The MAX6498 features an auto-retry mode that attempts to turn on the MOSFET when the voltage falls to 130 mV. Three of the devices (MAX6495/MAX6496/MAX6499) can also be configured as a voltage limiter that provides a regulated output to allow for continuous operation. An internal charge pump on all circuits provides a 10 V gate-to-source enhancement to minimize drain-to-source resistance during normal operation. Other features include a POK indicator (MAX6497/MAX6498) and the control logic for driving a p-channel MOSFET to provide reverse battery protection. All devices offer a shutdown input. These protection circuits are offered in a 3 mm by 3 mm TDFN package and are fully specified from -40 °C to 125 °C. Prices for these devices start at $1.23 in 1000-unit quantities.
Maxim Integrated Products • (408)

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