LM3743 - High-Performance Synchronous Buck Controller with Comprehensive Fault Protection Features from the PowerWise® Family

Datasheet Packaging Samples & Pricing Eval. Boards Reliability Design Tools Knowledge Base

Features



•Input voltage from 3.0V to 5.5V
•Output voltage adjustable down to 0.8V
•Reference accuracy: ±1.75%, over full temperature and input voltage range
•High-side and Low-side N-Channel MOSFETs
•Switching frequency options of 1 MHz or 300 kHz
•Comprehensive Fault Protection Features:
• High-side current limit
• Low-side current limit
• Output under-voltage protection
•Hiccup mode protection eliminates thermal runaway during fault conditions
•Externally programmable soft-start with tracking capability
•Pre-bias start-up capability
•MSOP-10 package

General Description

The LM3743 is a DC-DC voltage mode PWM buck controller featuring synchronous rectification at 300 kHz or 1 MHz. More...


Applications

•Rack-mount servers
•Telecom base stations
•Routers
•Printers/Scanners
•Multi-media set-top boxes
•FPGAs, ASICs, and DSPs
  Typical Application
click for larger image


Parametric Table     expand
Parametric Table    collapse
Output Current 10000 mA
Input Min Voltage 3 Volt
Input Max Voltage 5.5 Volt
Feedback Voltage 0.8 Volt
Feedback Tolerance 1.75 %
Frequency Min 300 kHz
Frequency Max 1000 kHz
Efficiency (peak) 95 %
Output Current 10000 mA
Input Min Voltage 3 Volt
Input Max Voltage 5.5 Volt
Feedback Voltage 0.8 Volt
Feedback Tolerance 1.75 %
Frequency Min 300 kHz
Frequency Max 1000 kHz
Efficiency (peak) 95 %
Output Range 0.8V to 4.6V
Adj Switch Frequency No
Adjustable Output Yes
Synchronous Rectification Yes
On/Off Pin Yes
Error Flag No
SoftStart Yes
Sync Pin No
Inverting No
Flyback No
Lossless Current Sense Yes
RegType Switching Regulator
Temperature Min -40 deg C
Temperature Max 125 deg C
Channels 1 Channels
Special Features Pre-bias start-up; Hiccup mode; External programmable soft-start and tracking
Topology Buck
PWM Mode Voltage
Step-Down Yes
Step-Up No
Output Power Undefined Watt
Output Max 4.6 Volt
Output Min 0.8 Volt
PowerWise Yes
View Using Catalog


Typical Performance

*click for larger image

300 kHz, Vout = 2.5V
  Also Recommended
LM1770SOT23 Synchronous Buck Controller
LM1771Synchronous Buck Controller With Precision Enable
LM2743Synchronous Buck Controller With Vin Up To 16V

Additional Resources

Design Tools (see below)


Block Diagram

click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM3743 High-Performance Synchronous Buck Controller with Comprehensive Fault Protection Features 590 Kbytes 7-Oct-08 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
LM3743-1000EVALN-Channel FET Synchronous Buck Regulator Controller for Low Output VoltagesFull productionN/A
 
Buy Now 		1+$77.301-
8 weeksN/A
LM3743-300EVALN-Channel FET Synchronous Buck Regulator Controller for Low Output VoltagesFull productionN/A
 
Buy Now 		1+$77.301-
8 weeksN/A
LM3743MM-1000MINI SOIC10NOPB1260RoHS Download Full productionN/A
Samples
Buy Now 		1K+$1.10reel
of
1000		ZXTT
SKNB
6 weeks50
LM3743MM-300MINI SOIC10NOPB1260RoHS Download Full productionN/A
Samples
Buy Now 		1K+$1.00reel
of
1000		ZXTT
SKPB
6 weeks1000
LM3743MMX-1000MINI SOIC10NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.10reel
of
3500		ZXTT
SKNB
6 weeksN/A
LM3743MMX-300MINI SOIC10NOPB1260RoHS Download Full productionN/A
 
Buy Now 		1K+$1.00reel
of
3500		ZXTT
SKPB
6 weeksN/A

General Description

The LM3743 is a DC-DC voltage mode PWM buck controller featuring synchronous rectification at 300 kHz or 1 MHz. It can deliver current as high as 20A and step down from an input voltage between 3V and 5.5V down to a minimum output voltage of 0.8V, with a ±1.75% internal reference accuracy. The LM3743 provides a set of comprehensive fault protection features such as high-side current limit, output under-voltage protection, and low-side current limit. When any of these fault protection features are engaged, it enters a hiccup protection mode which is suitable for high reliability systems such as rack mounted servers and telecom base station subsystems. The LM3743 also employs a proprietary monolithic glitch free pre-bias start-up method suited for FPGA and ASIC logic devices. An external programmable soft-start allows for tracking and timing flexibility. The driver features 1.6Ω of pull-up resistance and 1Ω of pull-down drive resistance for high power density and very efficient power processing.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM3743MM-1000PVIP05009600007650005217070838
LM3743MM-300PVIP05009600007650005217070838
LM3743MMX-1000PVIP05009600007650005217070838
LM3743MMX-300PVIP05009600007650005217070838

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.


Design Tools

TitleSize in Kbytes Date Click link below to Download    
Voltage Mode Compensation of Buck Regulators     View    

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Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-1669: Application Note 1669 LM3743 High Performance Controller with Comprehensive Fault Protection Features Designed for High Reliability Systems 118 Kbytes 19-Jun-07 Download
AN-1669 (Japanese): Application Note 1669 LM3743 High Performance Controller with Comprehensive Fault Protection Features Designed for High Reliability Systems
 92 Kbytes   Download
AN-1669 (Chinese): Application Note 1669 LM3743 High Performance Controller with Comprehensive Fault Protection Features Designed for High Reliability Systems
 214 Kbytes  
AN-1450: Application Note 1450 LM3743 Evaluation Board 694 Kbytes 12-Sep-06 Download
AN-1450 (Chinese): Application Note 1450 LM3743 Evaluation Board
 365 Kbytes  

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[Information as of 4-Jul-2009]