The LTC1149CN#PBF is a synchronous step-down switching Regulator Controller features automatic Burst Mode® operation to maintain high efficiencies at low output currents. This device drive external complementary power MOSFETs at switching frequencies up to 250kHz using a constant OFF-time current-mode architecture. Special onboard regulation and level-shift circuitry allow operation at input voltage from dropout to 48V (60V absolute maximum). The constant OFF-time architecture maintains constant ripple current in the inductor, easing the design of wide input range converters. Current-mode operation provides excellent line and load transient response. The operating current level is user-programmable via an external current sense resistor. The LTC1149 series incorporates automatic power saving Burst Mode® operation when load currents drop below the level required for continuous operation. Standby power is reduced to only about 8mW at VIN=12V. In shutdown, both MOSFETs are turned off.
● Up to 95% ultrahigh efficiency
● Current-mode operation for excellent line and load transient response
● High efficiency maintained over wide current range
● Logic-controlled micropower shutdown
● Short-circuit protection
● 100% Duty cycle very low dropout operation
● Synchronous FET switching for high efficiency
● Adaptive non-overlap gate drives
