Typical Application Circuit for LTC3728LEUH-1 High Efficiency Low Noise 5V/3A, 3.3V/5A, 12V/120mA Regulator. The LTC3728L-1 is a dual high performance step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows phase-lockable frequency of up to 550kHz