Features • 10-lead MSOP package • Internal push-pull driver with 1A peak current capability • Current limit and thermal shutdown • Frequency compensation optimized with a capacitor and a resistor • Internal softstart • Current Mode Operation • Adjustable Undervoltage Lockout with Hysteresis • Pulse Skipping at Light Loads Description The LM3481 is a versatile Low-Side N-FET high performance controller for switching regulators. It is suitable for use in topologies requiring a low-side FET, such as boost, flyback, SEPIC, etc. The LM3481 can be operated at extremely high switching frequencies in order to reduce the overall solution size. The switching frequency of the LM3481 can be adjusted to any value between 100 kHz and 1 MHz by using a single external resistor or by synchronizing it to an external clock. Current mode control provides superior bandwidth and transient response in addition to cycle-by-cycle current limiting. Current limit can be programmed with a single external resistor. The LM3481 has built in protection features such as thermal shutdown, short-circuit protection and over voltage protection. Power saving shutdown mode reduces the total supply current to 5µA and allows power supply sequencing. Internal soft-start limits the inrush current at start-up. Key Specification • Wide supply voltage range of 2.97V to 48V • 100 kHz to 1 MHz Adjustable and Synchronizable clock frequency • ±1.5% (over temperature) internal reference • 10 µA shutdown current (over temperature) Applications • Distributed Power Systems • Notebook, PDA, Digital Camera, and other Portable Applications • Offline Power Supplies • Set-Top Boxes

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

Title		Size	Date	Other Language
	LM3481 High Efficiency Low-Side N-Channel Controller for Switching Regulators	449 Kbytes	16-Nov-07	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-1756: Application Note 1756 LM3481 Evaluation Board	505 Kbytes	30-Apr-08	日本語

More Application Notes

Title		Size	Date	Other Language
	AN-1204: Application Note 1204 LM3478/LM3488 Evaluation Board	218 Kbytes	10-May-04

Design Tools

Title	Size	Date
Current Mode Modeling - Reference Guide	1372 Kbytes	1-Aug-2007
Understanding and Applying Current-Mode Control Theory	427 Kbytes	8-Jan-2008
"Article - How to supply, load, and test power-management circuits Part 1"
Article - Supplying and Loading of Power Management Circuits Part 3

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM3481MM	ABCD5	0	5364	0	0	1626984	3	461661152
LM3481MMX	ABCD5	0	5364	0	0	1626984	3	461661152

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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