The TPS60101 step-up, regulated charge pump generates a 3.3-V ±4% output voltage from a 1.8-V to 3.6-V input voltage (two alkaline, NiCd, or NiMH batteries). Output current is 100 mA from a 2-V input. Only four external capacitors are needed to build a complete low-noise dc/dc converter. The push-pull operating mode of two single-ended charge pumps assures the low output voltage ripple as current is continuously transferred to the output. From a 2-V input, the TPS60101 can start into full load with loads as low as 33 Ω.The TPS60101 features either constant frequency mode to minimize noise and output voltage ripple or the power-saving pulse-skip mode to extend battery life at light loads. The TPS60101 switching frequency is 300 kHz.