MAX16126/MAX16127 – protect power-supply inputs from automotive voltage transients

MAX16126/MAX16127 – protect power-supply inputs from automotive voltage transients


MAX16126/MAX16127 – protect power-supply inputs from automotive voltage transients, including load dump

The MAX16126/MAX16127 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 to ensure 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 MAX16126/MAX16127 use external resistors to adjust the overvoltage and undervoltage comparator thresholds for maximum flexibility.

The MAX16127 provides limiter-mode fault management for overvoltage and thermal shutdown conditions; whereas the MAX16126 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 MAX16126/MAX16127 are available in 12-pin TQFN packages. These devices operate over the automotive temperature range (-40°C to +125°C).

Key features

  • 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
  • AEC-Q100 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 MOSFETs
    • Adjustable Undervoltage/Overvoltage Thresholds
    • 3mm x 3mm, 12-Pin TQFN Package
  • Reduced Power Dissipation Compared to Discrete Solutions
    • Minimal Operating Voltage Drop for Reverse- Voltage Protection
    • 350µA (max) Supply Current and 100µA (max) Shutdown Current at 30V Input


  • Automotive
  • Avionics
  • Industrial
  • Telecom/Server/Networking

Block Diagram

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Mike is the founder and editor of, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)

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