Triple output converter from Linear Technology

The LTC3100’s boost converter operates from an input voltage range of 0.65V (start-up) to 5V making it compatible with single or multiple cell alkaline/NiMH and single cell Li-Ion/Polymer batteries and can deliver output voltages from 1.5V to 5.25V. The 250mA buck converter can be run directly from the output of the boost converter or from an independent 1.8V to 5.5V input and can deliver outputs as low as 0.6V. The LDO’s input is tied to the output of the boost converter and requires only 130mV of dropout voltage offering an additional low noise output adjustable down to 0.6V.

The combination of a boost, buck and LDO make the LTC3100 ideal for applications powered by low voltage inputs, such as single or dual cell alkaline batteries. For example: from a single cell alkaline input, the synchronous boost converter can deliver a higher voltage rail, such as 3.3V for microprocessor I/O, then the LDO will deliver a 3.0V output for memory and the synchronous step-down (connected to the output of the boost regulator) regulator can deliver a 1.0V VCORE rail. Synchronous rectification enables efficiencies of over 90% and Burst Mode® operation lowers quiescent current to only 15uA, providing extended battery run-time. Constant 1.5MHz frequency operation ensures low noise and high efficiency operation with tiny external inductors and capacitors.

The boost converter in the LTC3100 incorporates an integrated output disconnect function for reliable operation and also regulates when VIN>VOUT, extending usable battery run-time. Its output voltage is adjustable between 1.5V and 5.25V. Both switching converters offer internal compensation, soft start and have separate Power Good pins. All three channels have independent enable pins for power sequencing. For low noise applications, the Burst Mode feature can be replaced with a lower noise forced continuous mode via an external MODE pin. Offered in a 3mm x 3mm QFN-16 package, the LTC3100 offers a very compact solution footprint.