MAX863

19-1218; Rev 1; 6/97 UA IT MAN TION K E A U L A EV BL AVAILA L Dual, High-Efficiency, PFM, Step-Up DC-DC Controller ____________________________Features o Smallest Dual Step-Up Converter: 16-Pin QSOP o 90% Efficiency o 1.5V Start-Up Voltage o 85µA Max Total Quiescent Supply Current o 1µA Shutdown Mode o Independent Shutdown Inputs o Drives Surface-Mount, Dual N-Channel MOSFETs o Low-Battery Input/Output Comparator o Step-Up/Down Configurable _______________General Description The MAX863 dual-output DC-DC converter contains two independent step-up controllers in a single compact package. This monolithic bi-CMOS design draws only 85µA when both controllers are on. The input range extends down to 1.5V, permitting use in organizers, translators, and other low-power hand-held products. The MAX863 provides 90% efficiency at output loads from 20mA to over 1A. This space-saving device is supplied in a 16-pin QSOP package that fits in the same area as an 8-pin SOIC. The device uses a current-limited, pulse-frequencymodulated (PFM) control architecture that reduces startup surge currents and maintains low quiescent currents for excellent low-current efficiency. Each controller drives a low-cost, external, N-channel MOSFET switch, whose size can be optimized for any output current or voltage. In larger systems, two MAX863s can be used to generate 5V, 3.3V, 12V, and 28V from just two or three battery cells. An evaluation kit (MAX863EVKIT) is available to speed designs. For a single-o...