The LTC3851 has a wide input voltage range and can be powered from an intermediate bus voltage to produce output voltages of up to 5.5V. The powerful on-board MOSFET gate driver enables the use of high power external MOSFETs to develop output currents up to 20A at up to 95% efficiency and is ideal for point-of-load regulation applications. The difference between the LTC3851 and LTC3851-1 is that the LTC3851 has an adjustable current limit, and the LTC3851-1 has a fixed current limit and power good signal. A constant-frequency current mode architecture allows a selectable fixed or phase-lockable (PLL) frequency from 250kHz to 750kHz. OPTI-LOOP® compensation allows for a wide range of output capacitance and ESR values, including all ceramic input and output capacitors for the smallest solution size. The LTC3851 can be configured for coincident or ratiometric tracking for safe power-up and power-down of voltage timing sensitive DSPs, ASICs and FPGAs.