The AAT2138 is a high current synchronous step-down converter with an integrated current-limited load switch designed for high precision current control applications. By guarding against excessive input current, AAT2138 enables the system designer to maximize the output current from the step-down converter while protecting the input supply. It is designed for protection of USB ports from heavy load transient conditions commonly seen with high data rate modem applications.

AAT2138 integrates a high precision programmable current limited P-channel MOSFET load switch to protect the input supply against large currents which may cause the supply to fall out of regulation. The current limit threshold is programmed up to 3A by an external resistor between RSET and ground.

The AAT2138 is a 2.8MHz current mode step-down converter. It utilizes a tiny 1μH inductor and internal compensation to enable it to have an extremely small foot print. The regulator supports 100% duty cycle operation for dropout conditions. An external clock in the range of 1MHz to 3MHz can be fed into MODE as a synchronous signal for the step-down regulator. This feature offers the flexibility of fine tuning the switching frequency and optimizing performance in the application.

AAT2138 is available in a Pb-free, low profile, 14-pin 3mm x 3mm TDFN package. The product is rated over the -40°C to 85°C temperature range.