The LTC3111 is a fixed frequency, synchronous buckboost DC/DC converter with an extended input and output range. The unique 4-switch, single inductor architecture provides low noise and seamless operation from input voltages above, below or equal to the output voltage.With an input and output range of 2.5V to 15V, the LTC3111 is well suited for a wide variety of single or multiple-cell batteries, back-up capacitor or wall adapter source applications. Low RDS(ON)internal N-channel MOSFET switches and selectable PWM or Burst Mode operation produce high efficiency over a wide range of operating conditions. An accurate RUN pin allows the user to program the turn-on threshold voltage of the converter. Other features include: short-circuit protection, internal soft-start and thermal shutdown.The LTC3111 is offered in both thermally enhanced 14-lead (3mm × 4mm × 0.75mm) DFN and 16-lead MSOP packages.Applications3.3V or 5V from 1, 2 or 3 Li-Ion, Multiple-Cell Alkaline/NiMH BatteriesRF TransmittersMilitary, Industrial Power Systems