1.6MHz synchronous boost regulator with programmable input current limit

Linear Technology announces the LTC3125, a 1.6MHz, current mode, synchronous boost DC/DC converter with an accurate and programmable average input current limit. Its internal 1.2A switches can deliver output voltages as high as 5.25V from an input voltage range of 1.8V to 5.5V, making it dedicated for Li-Ion/Polymer, 3.3V PC card slot or multicell alkaline/NiMH applications. The LTC3125 can deliver up to 500mA of continuous output current (at 5V) from a 3.3V input. The LTC3125’s average input current limit can be programmed between 200mA and 1000mA with ±5% accuracy.

 The accurate adjustable current limit combined with an output reservoir capacitor makes the LTC3125 suitable for applications such as GSM and GPRS cards which demand 2A or higher current pulses from a power-limited input source. In addition, the LTC3125’s accurate input current enables safe and fast charging of large Super or Ultra-capacitors in battery backup systems without overstressing the battery or auxiliary power source. Synchronous rectification enables efficiencies up to 93% while Burst Mode operation lowers quiescent current to only 15uA, providing extended battery run-time in handheld applications. The LTC3125 can also operate in Buck mode, providing a regulated output lower than the input.

 The combination of a 2mm x 3mm DFN-8 package and a constant switching frequency of 1.6MHz minimize both inductor and capacitor sizes, providing a tiny solution footprint and profile required in PC-card applications. Additional features include short-circuit protection, soft-start, and thermal protection. LTC3125EDCB is available from stock in an 8-lead 2mm x 3mm DFN package. 1,000-piece pricing starts at $2.25 each.