1FEATURES

2• Low-Noise Fixed Frequency Operation

• 1.5V Output Voltage

• Li-Ion (3.6V) to 1.5V with 81% Efficiency

• 1.7% Output Voltage Accuracy

• Very Low Output Ripple: 8mV @ 250mA

• Output Currents up to 250mA

• 2.7V to 5.5V Input Range

• Shutdown Disconnects Load from VIN

• 1.1MHz Switching Frequency

• No Inductors…Small Solution Size

• Current Limit and Thermal Protection

• WSON-10 Package (3mm × 3mm × 0.8mm)

APPLICATIONS

• DSP, Memory, and Microprocessor Power

Supplies

• Mobile Phones and Pagers

• Portable Electronic Devices

DESCRIPTION

The LM2771 is a switched capacitor step-down

regulator that produces a 1.5V output without the use

of an inductor. It is capable of supplying loads up to

250mA. The LM2771 operates with an input voltage

from 2.7V to 5.5V, and requires only 3 low-cost

ceramic capacitors.

The LM2771 uses a regulated 0.5x charge pump to

give power conversion efficiencies nearly twice as

high as an LDO. Pre-regulated 1.1MHz fixed-

frequency switching results in very low ripple and

noise on both the input and the output. When output

currents are low (<30mA typ.), the part automatically switches to a low-ripple PFM regulation mode to

maintain high efficiency over the entire load range. At

input voltages below 3.5V (Typ), the charge pump

goes into pass mode, with efficiencies similar to an

LDO.