LM3477 - High Efficiency High-Side N-Channel Controller for Switching Regulator
Datasheet Packaging Samples & Pricing Eval. Boards Reliability Application Notes Knowledge Base

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

General Description

The LM3477/A is a high-side N-channel MOSFET switching regulator controller. More...


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
  Typical Application
click for larger image


ParametersValues
Output Current 6000 mA
Input Min Voltage 2.95 Volt
Input Max Voltage 35 Volt
Output Range 1.265V min
Frequency Min 500 kHz
Frequency Max 500 kHz
Feedback Voltage 1.265 Volt
Feedback Tolerance 1.5 %
Adj Switch Frequency No
Adjustable Output Yes
Synchronous Rectification No
On/Off Pin Yes
Error Flag No
SoftStart Yes
Sync Pin No
Inverting Yes
Flyback No
Lossless Current Sense No
RegType Switching Controller
Temperature Min -40 deg C
Temperature Max 125 deg C
Channels 1 Channels
Special Features Hysteretic threshold at 36% of programmed current limit; Vout OVP
Topology Buck
PWM Mode Current
Step-Down Yes
Step-Up No
Output Min 1.265 Volt


Typical Performance

*click for larger image


  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
Additional Resources
Online Seminars Application Notes


Block Diagram

click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM3477 High Efficiency High-Side N-Channel Controller for Switching Regulator 841
Kbytes		 20-Jul-04 Download
LM3477 High Efficiency High-Side N-Channel Controller for Switching Regulator (Japanese)
 886 Kbytes   Download

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Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders		Budgetary PricingStd
Pack
Size		Package
Marking
Format
TypePinsSpec.MSL
Rating		Peak
Reflow		RoHS
Report		CAD
Symbols		WeeksQtyQty$US each
LM3477EVALHigh Efficiency High-Side N-Channel Controller for Switching RegulatorFull productionN/A
 
Buy Now 		1+$30.001-
8 weeksN/A
LM3477AMMMINI SOIC8NOPB
STD		1
1		260
260		RoHS Download Full productionN/A
Samples
Buy Now 		1K+$0.90reel
of
1000		ZXTT
S13A
6 weeks2500
LM3477MMMINI SOIC8NOPB
STD		1
1		260
260		RoHS Download Full productionN/A
Samples
Buy Now 		1K+$0.90reel
of
1000		ZXTT
S13B
6 weeks2000
LM3477AMMXMINI SOIC8NOPB
STD		1
1		260
260		RoHS Download Full productionN/A
 
Buy Now 		1K+$0.90reel
of
3500		ZXTT
S13A
6 weeks5000
LM3477MMXMINI SOIC8NOPB
STD		1
1		260
260		RoHS Download Full productionN/A
 
Buy Now 		1K+$0.90reel
of
3500		ZXTT
S13B
6 weeks7500

General 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.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM3477AMMABCD15003417500423400011201409060
LM3477AMMXABCD15003417500423400011201409060
LM3477MMABCD15003417500423400011201409060
LM3477MMXABCD15003417500423400011201409060

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.


Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-1149: Application Note 1149 Layout Guidelines for Switching Power Supplies 248
Kbytes		 1-May-04 Download
AN-1149 (Japanese): Application Note 1149 Layout Guidelines for Switching Power Supplies
 90 Kbytes   Download
AN-1193: Application Note 1193 LM3477 Evaluation Board 248
Kbytes		 10-May-04 Download

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More Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-1204: Application Note 1204 LM3478/LM3488 Evaluation Board 218
Kbytes		 10-May-04 Download
AN-1381: Application Note 1381 LM3475 Evaluation Board 457
Kbytes		 4-May-05 Download
AN-1286: Application Note 1286 Compensation For The LM3478 Boost Controller 204
Kbytes		 19-May-09 Download
AN-1286 (Japanese): Application Note 1286 Compensation For The LM3478 Boost Controller
 202 Kbytes   Download
AN-1286 (Chinese): Application Note 1286 Compensation For The LM3478 Boost Controller
 368 Kbytes  
AN-1484: Application Note 1484 Designing A SEPIC Converter 196
Kbytes		 30-Apr-08 Download
AN-1484 (Japanese): Application Note 1484 Designing A SEPIC Converter
 175 Kbytes   Download
AN-1484 (Chinese): Application Note 1484 Designing A SEPIC Converter
 338 Kbytes  

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[Information as of 8-Nov-2009]