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.