Load-Dump/Reverse-Voltage Protection Circuits

 

Part Number	Replacement	Explanation

Description

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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).

MAX16126, MAX16127: Functional Diagram Enlarge+

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

Applications/Uses

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