Features • 500kHz switching frequency • Adjustable current limit • 1.5% reference • Thermal shutdown • Frequency compensation optimized with a single capacitor and resistor • Internal softstart • Current mode operation • Undervoltage lockout with hysteresis • 8-lead Mini-SO8 (MSOP-8) package Description The LM3477/A is a high-side N-channel MOSFET switching regulator controller. It can be used in topologies requiring a high side MOSFET such as buck, inverting (buck-boost) and zeta regulators. The LM3477/A's internal push pull driver allows compatibility with a wide range of MOSFETs. This, the wide input voltage range, use of discrete power components and adjustable current limit allows the LM3477/A to be optimized for a wide variety of applications. The LM3477/A uses a high switching frequency of 500kHz to reduce the overall solution size. Current-mode control requires only a single resistor and capacitor for frequency compensation. The current mode architecture also yields superior line and load regulation and cycle-by-cycle current limiting. A 5µA shutdown state can be used for power savings and for power supply sequencing. Other features include internal soft-start and output over voltage protection. The internal soft-start reduces inrush current. Over voltage protection is a safety feature to ensure that the output voltage stays within regulation. The LM3477A is similar to the LM3477. The primary difference between the two is the point at which the device transitions into hysteretic mode. The hysteretic threshold of the LM3477A is one-third of the LM3477. Applications Local Voltage Regulation Distributed Power Notebook and Palmtop Computers Internet Appliances Printers and Office Automation Battery operated Devices Cable Modems Battery Chargers   Hysteretic Threshold LM3477 [Approximately_Equals] 36% of programmed current limit LM3477A [Approximately_Equals] 12% of programmed current limit

Also Recommended LM1770▲ Low-Voltage SOT-23 Synchronous Buck Controller LM2727▲ Synchronous, Low Voltage, 2MHz, Buck Controller LM2636▲ Digitally Controlled, 1MHz, Buck Controller LM2642▲ Dual, Multiphase, Buck Switching Controller LM3075▲ Synchronous, Medium Voltage, Buck Controller 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
	LM3477 High Efficiency High-Side N-Channel Controller for Switching Regulator	841 Kbytes	20-Jul-04	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-1149: Application Note 1149 Layout Guidelines for Switching Power Supplies	248 Kbytes	1-May-04	日本語
	AN-1193: Application Note 1193 LM3477 Evaluation Board	248 Kbytes	10-May-04

More Application Notes

Title		Size	Date	Other Language
	AN-1204: Application Note 1204 LM3478/LM3488 Evaluation Board	218 Kbytes	10-May-04
	AN-1381: Application Note 1381 LM3475 Evaluation Board	457 Kbytes	4-May-05
	AN-1286: Application Note 1286 Compensation For The LM3478 Boost Controller	204 Kbytes	19-May-09	日本語 中文
	AN-1484: Application Note 1484 Designing A SEPIC Converter	196 Kbytes	30-Apr-08	日本語 中文

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM3477AMM	ABCD150	0	34175	0	0	4234000	1	1201409060
LM3477AMMX	ABCD150	0	34175	0	0	4234000	1	1201409060
LM3477MM	ABCD150	0	34175	0	0	4234000	1	1201409060
LM3477MMX	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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