Electronic Design

Current-Limited Load Switch Simplifies Hot-Swap Management

The AAT4614 current-limited p-channel MOSFET power switch from Advanced Analogic Technologies targets high-side load-switching applications. Designed to protect peripheral ports from short-circuit and overvoltage events, it combines reverse current blocking with programmable current-limit capability and an integrated fault flag in a silicon footprint that’s up to 30% smaller than traditional implementations.

Operating across an input range of 2.4 to 5.5 V, the AAT4614 can be used in 3- and 5-V systems. When the input drops below 2.4 V, an undervoltage lockout (UVLO) circuit automatically shuts down operation to avoid saturation. To protect the device against large input currents that could cause the supply to fall out of regulation, the switch’s overcurrent threshold is programmable up to 1.6 A via a resistor from SET to ground. A 1-µs current-limit transient response reduces the requirements for local supply bypassing.

Also, the AAT4614’s reverse-current blocking capability protects the device from reverse-current potentials when disabled. Its open drain FAULT flag indicates overcurrent and overtemperature conditions. A 4-ms blanking time prevents false reporting during capacitive-load charging. And, the AAT4614 features a 130-mΩ typical on resistance.

To conserve power, the AAT4614’s quiescent current is only 10 µA. In shutdown mode, supply current decreases to less than 1 µA. Its overtemperature protection circuit automatically switches the device off if die temperature exceeds a pre-defined limit. The AAT4614 is qualified from –40°C to 85°C. The AAT4614 is available in a lead-free, eight-pin SC70JW package, a six-pin SOT23 package, or a five-pin SOT23 package. It costs $0.49 in 1000-unit quantities.

Advanced Analogic Technologies


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