Linear Technology H- and MP-grade LTC3851A DC/DC controller

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Linear Technology has announced the H- and MP-grade versions of the LTC3851A, a wide input voltage range (4 to 38 V) synchronous step-down DC/DC controller.

The strong onboard MOSFET gate drivers enable the use of high-power external MOSFETs to produce output currents up to 25 A with output voltages ranging from 0.8 to 5.5, suitable for point-of-load requirements. These H- and MP-grade versions are tested and guaranteed to operating junction temperature ranges from -40 to 150°C and -55 to 150°C.

A constant-frequency, current-mode architecture allows a selectable fixed or phase-locked loop frequency from 250 to 750 kHz. Output current sensing is accomplished by measuring the voltage drop across the output inductor or using an optional sense resistor.

Current foldback limits MOSFET heat dissipation during short-circuit and overload conditions. Selectable continuous, pulse skipping or Burst Mode operation is user controlled to optimise light load efficiency.

With up to 99% duty cycle, the LTC3851A/-1 has a low dropout voltage. Additional features include tracking and adjustable soft-start. The LTC3851A-1 differs from the LTC3851A in that it has a power good signal instead of adjustable current limit.