View ltc14389fa datasheet:

LTC1438/LTC1439 Dual High Efficiency, Low Noise, Synchronous Step-Down Switching Regulators FEATURES DESCRIPTION Maintains Constant Frequency at Low Output Currents The LTC®1438/LTC1439 are dual, synchronous step- Dual N-Channel MOSFET Synchronous Drive down switching regulator controllers which drive external Programmable Fixed Frequency (PLL Lockable) N-channel power MOSFETs in a phase-lockable fixed Wide VIN Range: 3.5V to 36V Operation frequency architecture. The Adaptive PowerTM output stage Ultrahigh Efficiency selectively drives two N-channel MOSFETs at frequencies Very Low Dropout Operation: 99% Duty Cycle up to 400kHz while reducing switching losses to maintain Low Dropout, 0.5A Linear Regulator for VPP high efficiencies at low output currents. Generation or Low