Features • 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 • LLP-10 Package (3mm × 3mm × 0.8mm) 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. The LM2771 is available in National's 10-pad Leadless Leadframe No-Pullback Package (LLP-10). Applications • DSP, Memory, and Microprocessor Power Supplies • Mobile Phones and Pagers • Portable Electronic Devices

MY BRIEFCASE                                       Click any "Briefcase" icon to add an item

Typical Application click for larger image	Block Diagram click for larger image
Typical Performance click for larger image

Datasheet

Title		Size	Date	Other Language
	LM2771 Low-Ripple 250mA Switched Capacitor Step-Down DC/DC Converter	890 Kbytes	9-Mar-06	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-1547: Application Note 1547 LM2771 Evaluation Board	670 Kbytes	3-Nov-06	中文

More Application Notes

Title		Size	Date	Other Language
	AN-1769: Application Note 1769 LM2773 Evaluation Board	419 Kbytes	2-Jun-08
	AN-1714: Application Note 1714 LM2772 Evaluation Board	391 Kbytes	18-Sep-07

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2771SD	CMOS7	0	18406	0	0	1089000	4	309006723
LM2771SDX	CMOS7	0	18406	0	0	1089000	4	309006723

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.