ADP2109

Data Sheet FEATURES Peak efficiency: 95% Discharge switch function Fixed frequency operation: 3 MHz Typical quiescent current: 18 μA Maximum load current: 600 mA Input voltage: 2.3 V to 5.5 V Uses tiny multilayer inductors and capacitors Current mode architecture for fast load and line transient response 100% duty-cycle low dropout mode Internal synchronous rectifier Internal compensation Internal soft start Current overload protection Thermal shutdown protection Shutdown supply current: 0.2 μA 5-ball WLCSP Supported by ADIsimPower™ design tool Compact 600 mA, 3 MHz, Step-Down Converter with Output Discharge ADP2109 GENERAL DESCRIPTION The ADP2109 is a high efficiency, low quiescent current stepdown dc-to-dc converter with an internal discharge switch that allows automatic discharge of the output capacitor in an ultrasmall 5-ball WLCSP package. The total solution requires only three tiny external components. It uses a proprietary high speed current mode and constant frequency pulse-width modulation (PWM) control scheme for excellent stability, and transient response. To ensure the longest battery life in portable applications, the ADP2109 has a power save mode that reduces the switching frequency under light load conditions. The ADP2109 runs on input voltages of 2.3 V to 5.5 V, which allow for single lithium or lithium polymer cell, multiple alkaline or NiMH cells, PCMCIA, USB, and other standard power sources. The maximum load current of 600 mA is achievable across the inpu...