DC761A - Schematic9/24/2009
Demonstration circuit 761 is a low noise regulated charge pump featuring the LTC3204 (Burst Mode operation) in the 2 × 2 DFN package. There are two assembly versions, DC761A-A and DC761A-B for the LTC3204-5 (5V output) and LTC3204-3.3 (3.3V output) respectively. The DC761A-B produces a regulated 3.3V output from a 1.8V to 4.5V input. The guaranteed output current is 50mA from VIN between 1.9V and 4.5V, and 40mA for VIN less than 1.9V.
The circuit requires only three tiny 0603 surface mount capacitors and uses minimal board space. No inductor or diodes are needed. The circuit features automatic Burst Mode® operation at light loads to maintain low supply current.