Linear Announces 1MHz Synchronous Boost Regulator

Linear Technology Corporation has introduced its LTC3539/-2, 1MHz/2MHz, current mode, synchronous boost DC/DC converters with output disconnect and integrated soft-start. Their internal 2A switches can deliver output voltages as high as 5.25V from an input voltage range of 0.70V at start-up, (0.5V when running) to 5V for Li-Ion/Polymer or single/multicell alkaline/NiMH applications. The LTC3539/-2 can deliver up to 900mA of continuous output current (at 3.3V) from dual alkaline cells or 900mA of continuous output current (at 5V) from a single-cell Li-Ion battery. The combination of a 2mm x 3mm DFN-8 package and a constant switching frequency of 1MHz (2MHz for the LTC3539-2) minimize both inductor and capacitor sizes, providing a tiny solution footprint required in handheld applications.



The LTC3539/-2 have internal switches with an RDS(ON) of only 0.09 Ohm (N-Channel) and 0.125 Ohm (P-Channel) to deliver efficiencies as high as 94%. The output disconnect feature allows the output to be discharged in shutdown. For applications demanding the lowest possible noise operation, the LTC3539/-2 can be set via an external pin to operate in a continuous frequency mode. This version runs in continuous mode at all current levels to minimize possible interference of switching noise with noise-sensitive circuitry slightly reducing light load efficiency. Additional features include anti-ringing control, short-circuit protection, soft-start, and thermal protection. The LTC3539/-2 delivers an ideal solution for boost applications requiring up to 900mA of output current and where a small solution size and low maximum battery run-time are defining factors. The LTC3539EDCB and LTC3539EDCB-2 are both available from stock in 8-lead 2mm x 3mm DFN packages. 1,000-piece pricing starts at $2.50 each.