Regulator Delivers 100 mA from Single Alkaline Cell

Sept. 6, 2006
Linear Technology's LTC3526 can deliver up to 100 mA of continuous output current from a single alkaline cell.

Linear Technology’s LTC3526 can deliver up to 100 mA of continuous output current (at 3.3 V) from a single alkaline cell. The device is a 1-MHz, current mode, synchronous boost dc-dc converter with output disconnect and integrated soft-start capability. Its internal 500-mA switches can deliver output voltages as high as 5 V from an input voltage range of 0.85 V to 4.4 V, making it suited for Li-Ion/Polymer or single/multicell alkaline/NiMH applications.

Synchronous rectification enables efficiencies of up to 94% while Burst Mode operation lowers quiescent current to only 9 μA, providing extended battery run-time in handheld applications. The combination of a 2-mm x 2-mm DFN-6 package and a constant switching frequency of 1 MHz minimize both inductor and capacitor sizes.

The LTC3526 uses internal switches with an RDS(ON) of only 0.40 Ω (N-Channel) and 0.60 Ω (P-Channel) to deliver efficiencies as high as 94%. 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. Additional features include anti-ringing control, short-circuit protection, soft-start, and thermal protection. The LTC3526 is a solution for boost applications requiring up to 200 mA of output current and where a small solution size and low maximum battery run-time are defining factors.

For applications demanding the lowest possible noise operation, a LTC3526B version is available with the Burst Mode feature disabled. The LTC3526B version runs in continuous mode at all current levels, slightly reducing light load efficiency. However, it minimizes possible interference of switching noise with onboard noise sensitive circuitry. LTC3526EDC and LTC3526BEDC are both available from stock in 6-lead DFN packages. The pricing for 1000-pieces starts at $1.75 each.

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