The LTC3124 from Linear Technology is a dual-phase, 3MHz, current-mode, synchronous boost DC/DC converter with output disconnect and inrush current limiting. Dual-phase operation significantly reduces peak inductor and capacitor ripple currents, minimizing component size while enabling the device to lower output ripple. Its internal 2.5A per phase capable switches together deliver 5A of switch current.
These 18V switches can deliver output voltages as high as 15V from an input voltage range of 1.8V at start-up (0.5V when running) to 5.5V, making it suitable for supercapacitor-based backup power systems and Li-Ion/Polymer or multicell NiMH applications. The LTC3124 delivers up to 1.5A of continuous output current at 12V from a 5V input.
Synchronous rectification enables efficiencies up to 95%, while Burst Mode operation lowers quiescent current to only 25µA, providing extended battery run time. The combination of its thermally enhanced 3mm x 5mm DFN-16 (or TSSOP-16) package and a constant switching frequency of up to 3MHz, which minimizes both inductor and capacitor size, provides a compact solution footprint required in handheld applications.
The LTC3124 has internal switches with an RDS(ON) of only 130mOhm (N-channel) and 200mOhm (P-channel) to deliver efficiencies as high as 95%. The output disconnect feature allows the output to be completely discharged in shutdown. It also limits the inrush of current during start-up, minimizing surge currents seen by the input supply. The device will also regulate the output voltage when the input voltage exceeds the output voltage, enabling compatibility with any battery chemistry.
For applications demanding the lowest possible noise operation, the LTC3124 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 external synchronization, output overvoltage protection, and robust short-circuit protection. The LTC3124 delivers an ideal solution for boost applications requiring outputs up to 15V where high efficiency, small solution size and high reliability are defining factors.