Features Power stage input voltage from 1V to 16V Control stage input voltage from 3V to 6V Output voltage adjustable down to 0.5V Power good flag and shutdown Output overvoltage and undervoltage detection External reference voltage 0.5V to 1.5V Low-side adjustable current sensing Adjustable soft-start Tracking and sequencing with shutdown and soft start pins Switching frequency from 50 kHz to 1 MHz TSSOP-14 package Description The LM2744 is a high-speed synchronous buck regulator controller with an externally adjustable reference voltage (between 0.5V to 1.5V). It can provide simple down conversion to output voltages as low as 0.5V. Though the control sections of the IC are rated for 3 to 6V, the driver sections are designed to accept input supply rails as high as 16V. The use of adaptive non-overlapping MOSFET gate drivers helps avoid potential shoot-through problems while maintaining high efficiency. The IC is designed for the more cost-effective option of driving only N-channel MOSFETs in both the high-side and low-side positions. It senses the low-side switch voltage drop for providing a simple, adjustable current limit. The fixed-frequency voltage-mode PWM control architecture is adjustable from 50 kHz to 1 MHz with one external resistor. This wide range of switching frequency gives the power supply designer the flexibility to make better tradeoffs between component size, cost and efficiency. Features include soft-start, input undervoltage lockout (UVLO) and Power Good (based on both undervoltage and overvoltage detection). In addition, the shutdown pin of the IC can be used for providing startup delay, and the soft-start pin can be used for implementing precise tracking, for the purpose of sequencing with respect to an external rail. Applications 3.3V Buck Regulation Cable Modem, DSL and ADSL Laser Jet and Ink Jet Printers Low Voltage Power Modules DSP, ASIC, Core and I/O DDR Memory Termination Supply

Also Recommended LM4140 High Accuracy, Sub-Bandgap Stand-Alone Voltage Reference LP2996▲ DDR And DDR-II Linear Termination Regulator LP2997▲ DDR-II Linear Termination Regulator

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

Parameters / Values	LM2744	LP2996	LP2997
Input Min Voltage	1 Volt	1.5 Volt	2.2 Volt
Input Max Voltage	16 Volt	5.5 Volt	5.5 Volt
Output Current	20000 mA	1500 mA	500 mA
Standards	DDR2, DDR	DDR2, DDR	DDR2
Frequency Min	50 kHz
Frequency Max	2000 kHz
External Components	23	4	3
Independent Power/Analog Rails	Yes	No	Yes
On/Off Pin	Yes	Yes	Yes
Thermal Protection	No	Yes	Yes
Special Features	External Vref version of LM2743 for ultra-high accuracy; Tracking; Sequencing	Suspend to RAM shutdown	Suspend to RAM shutdown
PowerGood / Error Flag	Yes	No	No
Quiescent Current	1.5 mA	0.32 mA	0.32 mA
RegType	Switching Controller	LDO	LDO
Temperature Min	-40 deg C	0 deg C	0 deg C
Temperature Max	125 deg C	125 deg C	125 deg C
PowerWise	Yes

Datasheets

Title		Size	Date	Other Language
	LM2744 Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference	526 Kbytes	18-Jan-12

Application Notes

Title		Size	Date	Other Language
	AN-1357: Application Note 1357 LM2744 Evaluation Board	1794 Kbytes	5-Oct-05	中文
	AN-1603: Application Note 1603 LM274X Reference Designs	431 Kbytes	6-Dec-07	中文
	AN-1437: Application Note 1437 Current Limit Foldback Improves Short Circuit Protection in LM2743/44 Family	470 Kbytes	25-May-06	中文

Other Technical Documents

Title		Type	Date
	Power Management Considerations for FPGAs and ASICs	Power Designer	2007-03-22
	Optimizing Power Controller Designs through Effective Utilization of Performance Features (Adj Frequency & Sync, Ext Ref, Tracking, & Precision Enable)	Power Designer	2008-04-24

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM2744MTC/NOPB LM2744MTC RoHS Status	TSSOP	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 354 MOUSER Worldwide 278 RS COMPONENTS Worldwide 85 TAYLOR Americas 282	$1.15 each at 1K+ pcs	rail of 94
LM2744MTCX/NOPB LM2744MTCX RoHS Status	TSSOP	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$1.15 each at 1K+ pcs	reel of 2500

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 LM2744.

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 LM2744 is located at RoHS Status.

Part Number(s) (NSID)	Description	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM2744EVAL	Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference	Full production	Distributor Region Qty DIGI-KEY Worldwide 0	$79.70 each	1
Description: LM2744 Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference Features: Power stage input voltage from 1V to 16V Control stage input voltage from 3V to 6V Output voltage adjustable down to 0.5V Power good flag and shutdown Output overvoltage and undervoltage detection External reference voltage 0.5V to 1.5V Low-side adjustable current sensing Adjustable soft-start Tracking and sequencing with shutdown and soft-start pins Switching frequency from 50 kHz to 1MHz TSSOP-14 package Applications: 3.3V Buck Regulation Cable Modem, DSL and ADSL Laser Jet and Ink Jet Printers Low Voltage Power Modules DSP, ASIC, Core and I/O DDR Memory Termination Supply Contents: A fully assembled LM2744 evaluation board LM2744 datasheet LM2744 evaluation board appnote

National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C1) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/en/packaging/greennopb.html. Lead free products are RoHS compliant.

Lead Free product status is available through the search tool located here

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LM2744MTC/NOPB LM2744MTC	53.783 54.004	TSSOP	14	1 1	260 260	Detail	Download	N/A	NSZXYTT 2744 MTC
LM2744MTCX/NOPB LM2744MTCX	53.783 54.004	TSSOP	14	1 1	260 260	Detail	Download	N/A	NSZXYTT 2744 MTC

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 LM2744.

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 LM2744 is located at RoHS Status.

Design Tools

Title	Size	Date
Article - Exploit Controller Features to Optimize Power Designs

CAD Symbols and Models Download LM2744 CAD Symbols

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2744MTC	ABCD150	0	42680	0	0	6394000	1	1814314958
LM2744MTCX	ABCD150	0	42680	0	0	6394000	1	1814314958

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 LM2744.

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 LM2744 is located at RoHS Status.