Overvoltage protection controller MAX4864L-MAX4867 features/typical applications

The MAX4864L/MAX4865L/MAX4866L/MAX4867 overvoltage protection controllers protect low-voltage systems from voltage faults ranging from +28V to -28V. These devices drive a low-cost complementary MOSFET. If the input voltage is greater than the overvoltage threshold, these devices turn off the n-channel MOSFET to prevent damage to the protection components. If the input voltage is below ground, the devices turn off the p-channel MOSFET to prevent damage to the protection components. The devices use an internal charge pump to drive the MOSFET GATEN without external capacitors for a simple, effective solution.

The overvoltage thresholds are preset to +7.4V (MAX4864L), +6.35V (MAX4865L), +5.8V (MAX4866L), and +4.65V (MAX4867). When the input voltage falls below the undervoltage lockout (UVLO) threshold, the device enters a low-current standby mode (8.5uA). In shutdown mode (active-low EN set to logic high), the current is further reduced (0.4uA). The UVLO threshold for the MAX4864L/MAX4865L/MAX4866L is +2.85V, and the UVLO threshold for the MAX4867 is +2.5V.

Additionally, bypassing the input to ground with a 1uF capacitor provides ±15kV ESD protection. All devices are available in small 6-lead SOT23 and 6-lead, 2mm x 2mm uDFN packages and operate over the -40°C to +85°C temperature range.

Functional Block Diagram

Key Features

● Up to +28V overvoltage protection

● Reverse protection down to -28V

● Preset overvoltage (OV) levels (7.4V, 6.35V, 5.8V, 4.65V)

● Drive low-cost complementary MOSFET

● Internal 50ms start-up delay

● Internal charge pump

● 8.5uA standby current (UVLO mode)

● 0.4uA shutdown current

● Overvoltage fault FLAG indication

● 6-pin (2mm x 2mm) DFN and 6-pin SOT23 packages

Typical working circuit

application

Cellular phone

Digital camera

● MP3 player

● PDA and handheld computer devices