The AP1603 is a high efficiency step-up DC/DCconverter for applications using 1 to 2 NiMH batterycells. Only three external components are requiredto deliver a fixed output voltage of 3.3V. TheAP1603 starts up from less than 0.9V input with1mA load. Pulse Frequency Modulation schemebrings optimized performance for applications withlight output loading and low input voltages. Theoutput ripple and noise are lower compared with thecircuits operating in PSM mode.The PFM control circuit operating in 150KHz (max.)switching rate results in smaller passivecomponents. The space saving SOT23-6 packagesmake the AP1603 an ideal choice of DC/DCconverter for space conscious applications, likepagers, electronic cameras, and wireless microphones.