[MaximIC]

Device Description

A. General

The MAX1820 low-dropout, pulse-width-modulated (PWM) DC-DC buck regulator is optimized to provide power to the power amplifier (PA) in WCDMA cell phones; however, it may be applied in many other applications where high efficiency is a priority. The supply voltage range is from 2.6V to 5.5V, and the guaranteed output current is 600mA; 1MHz PWM switching allows for small external components, while skip mode reduces quiescent current to 180µA with light loads.

The MAX1820 is dynamically controlled to provide varying output voltages from 0.4V to 3.4V. The circuit is designed such that the output voltage settles in <30µs for a full-scale change in voltage and current.

The MAX1820 includes a low on-resistance internal MOSFET switch and synchronous rectifier to maximize efficiency and minimize external component count; 100 duty-cycle operation allows for low dropout of only 150mV at 600mA load, including the external inductor resistance. The device is offered in 10-pin µMAX and tiny 3 x 4 chip-scale (UCSP™) packages