Load-Dump/Reverse-Voltage Protection Circuits

The MAX16128/MAX16129 load-dump/reverse-voltage protection circuits protect power supplies from damaging input-voltage conditions, including overvoltage, reverse-voltage, and high-voltage transient pulses. Using a built-in charge pump, the devices control two external back-to-back n-channel MOSFETs that turn off and isolate downstream power supplies during damaging input conditions, such as an automotive load-dump pulse or a reverse-battery condition. Operation is guaranteed down to 3V that ensures proper operation during automotive cold-crank conditions. These devices feature a flag output (active-low FLAG) that asserts during fault conditions.

For reverse-voltage protection, external back-to-back MOSFETs outperform the traditional reverse-battery diode, minimizing the voltage drop and power dissipation during normal operation.

The devices use fixed overvoltage and undervoltage thresholds, minimizing the external component count.

The MAX16129 provides limiter-mode fault management for overvoltage and thermal-shutdown conditions; whereas the MAX16128 provides switch-mode fault management for overvoltage and thermal shutdown conditions. In the limiter mode, the output voltage is limited and active-low FLAG is asserted low during a fault. In the switch mode, the external MOSFETs are switched off and active-low FLAG is asserted low after a fault. The switch mode is available in four options—Latch mode, 1 Autoretry mode, 3 Autoretry mode, and Always autoretry mode.

The MAX16128/MAX16129 are available in an 8-pin µMAX® package and operate over the automotive temperature range (-40°C to +125°C).

Applications

* Automotive

* Avionics

* Industrial

* Telecom/Server/Networking

* Increases Protection of Sensitive Electronic Components in Harsh Environments

* -36V to +90V Wide Input-Voltage Protection Range

* Fast Gate Shutoff During Fault Conditions with Complete Load Isolation

* Thermal Shutdown Protection

* Active-Low FLAG Output Identifies Fault Condition

* Automotive Qualified

* Operates Down to +3V, Riding Out Cold-Crank Conditions

* -40°C to +125°C Operating Temperature Range

* Integration Reduces Solution Size

* Internal Charge-Pump Circuit Enhances External n-Channel MOSFET

* Fixed Undervoltage/Overvoltage Thresholds

* 3mm × 3mm, 8-Pin µMAX Package

* Reduced Power Dissipation Compared to Discrete Solutions

* Minimal Operating Voltage Drop for Reverse-Voltage Protection

* 380µA Supply Current and 100µA Shutdown Current at 30V Input

* Enables Functional Safety at System Level