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

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

Datasheets

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

Application Notes

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

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM2771SD/NOPB LM2771SD RoHS Status	LLP	Full production Lead Time: 6 weeks	Distributor Region Qty AVNET-EM Worldwide 1000 DIGI-KEY Worldwide 3054 MOUSER Worldwide 1000	$0.85 each at 1K+ pcs	reel of 1000
LM2771SDX/NOPB LM2771SDX RoHS Status	LLP	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$0.85 each at 1K+ pcs	reel of 4500

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM2771.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM2771 is located at RoHS Status.

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LM2771SD/NOPB LM2771SD	21.112 21.182	LLP	10	1 1	260 260	Detail	Download	N/A	ZXYTT L2771
LM2771SDX/NOPB LM2771SDX	21.112 21.182	LLP	10	1 1	260 260	Detail	Download	N/A	ZXYTT L2771

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM2771.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM2771 is located at RoHS Status.

CAD Symbols and Models Download LM2771 CAD Symbols

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2771SD	CMOS7	0	21301	0	0	1584000	3	449464325
LM2771SDX	CMOS7	0	21301	0	0	1584000	3	449464325

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.

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM2771.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM2771 is located at RoHS Status.