Features • ±1% feedback voltage accuracy over temperature • Switching frequency from 50 kHz to 1 MHz • Switching frequency synchronize range 250 kHz to 1 MHz • Startup with a pre-biased output load • Power stage input voltage from 1V to 14V • Control stage input voltage from 3V to 6V • Output voltage adjustable down to 0.6V • Power Good flag and shutdown • Output overvoltage and undervoltage detection • Low-side adjustable current sensing • Adjustable soft-start • Tracking and sequencing with shutdown and soft start pins • TSSOP-14 package Description The LM2747 is a high-speed synchronous buck regulator controller with a feedback voltage accuracy of ±1%. It can provide simple down conversion to output voltages as low as 0.6V. Though the control section of the IC is rated for 3 to 6V, the driver section is designed to accept input supply rails as high as 14V. 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 LM2747 features a fixed-frequency voltage-mode PWM control architecture which is adjustable from 50 kHz to 1 MHz with one external resistor. In addition, the LM2747 also allows the switching frequency to be synchronized to an external clock signal over the range of 250 kHz to 1 MHz. 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 the ability to startup with a pre-biased load on the output, 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 • Down Conversion from 3.3V • Cable Modem, DSL and ADSL • Laser Jet and Ink Jet Printers • Low Voltage Power Modules • DSP, ASIC, Core and I/O

Also Recommended LM2743▲ Synchronous Buck Controller With Tracking And Soft-Start LM2745▲ +/- 1.5% Accuracy LM3743▲ Low-Voltage Synchronous Buck Controller In MSOP-10 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
	LM2747 Synchronous Buck Controller with Pre-bias Startup, and Optional Clock Synchronization	1052 Kbytes	2-Mar-06	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-1449: Application Note 1449 LM2747 Evaluation Board	594 Kbytes	11-Apr-06
	AN-1641: Application Note 1641 LM2747-19A Demo Board	2571 Kbytes	17-May-07
	AN-1603: Application Note 1603 LM274X Reference Designs	431 Kbytes	6-Dec-07	中文

More Application Notes

Title		Size	Date	Other Language
	AN-1437: Application Note 1437 Current Limit Foldback Improves Short Circuit Protection in LM274X Family	470 Kbytes	25-May-06	中文
	AN-1573: Application Note 1573 LM2745-19A Demo Board	2572 Kbytes	17-May-07
	AN-1640: Application Note 1640 LM2743-19A Demo Board	2570 Kbytes	17-May-07	中文
	AN-1357: Application Note 1357 LM2744 Evaluation Board	1794 Kbytes	5-Oct-05	中文
	AN-1325: Application Note 1325 LM2742 Evaluation Board	607 Kbytes	1-Apr-04
	AN-1385: Application Note 1385 LM2746 Evaluation Board	1743 Kbytes	1-Jun-05	中文
	AN-1356: Application Note 1356 LM2743 Evaluation Board	1785 Kbytes	5-Oct-05	日本語 中文

Design Tools

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

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2747MTC	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2747MTCX	ABCD150	0	34175	0	0	4234000	1	1201409060

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.

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