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
LM1770Low-Voltage SOT-23 Synchronous Buck Controller
LM2727Synchronous, Low Voltage, 2MHz, Buck Controller
LM2636Digitally Controlled, 1MHz, Buck Controller
LM2642Dual, Multiphase, Buck Switching Controller
LM3075Synchronous, 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]