The LTC1266 series is a family of synchronous switching regulator controllers featuring automatic Burst Mode™operation to maintain high efficiencies at low output currents. These devices drive external power MOSFETs at switching frequencies up to 400kHz using a constant off-time current mode architecture providing constant ripple current in the inductor. They can drive either an N-channel or a P-channel topside MOSFET.The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 3.5V to 18V (20V maximum). Constant off-time architecture provides low dropout regulation limited only by the RDS(ON)of the topside MOSFET (when using the P-channel) and the resistance of the inductor and current sense resistor.The LTC1266 series combines synchronous switching for maximum efficiency at high currents with an automatic low current operating mode, called Burst Mode operation, which reduces switching losses. Standby power is reduced to only 1mW at VIN= 5V (at IOUT= 0). Load currents in Burst Mode operation are typically 0mA to 500mA.ApplicationsNotebook and Palmtop ComputersPortable InstrumentsCellular TelephonesDC Power Distribution SystemsGPS Systems