LM3475   
Hysteretic PFET Buck Controller 		Click link to Download

Features
•Easy to use control methodology
•0.8V to VIN adjustable output range
•High Efficiency (90% typical)
•±0.9% (±1.5% over temp) feedback voltage
•100% duty cycle capable
•Maximum operating frequency up to 2MHz
•Internal Soft-Start
•Enable pin
•SOT23-5 package

Description

The LM3475 is a hysteretic P-FET buck controller designed to support a wide range of high efficiency applications in a very small SOT23-5 package. The hysteretic control scheme has several advantages, including simple system design with no external compensation, stable operation with a wide range of components, and extremely fast transient response. Hysteretic control also provides high efficiency operation, even at light loads. The PFET architecture allows for low component count as well as 100% duty cycle and ultra-low dropout operation.

Applications
•TFT Monitor
•Auto PC
•Vehicle Security
•Navigation Systems
•Notebook Standby Supply
•Battery Powered Portable Applications
•Distributed Power Systems
Also Recommended
LM1770▲Low-Voltage SOT-23 Synchronous Buck Controller
LM1771▲Low-Voltage Synchronous Buck Controller With Precision Enable
LM2743▲Sync Buck Controller - 2A To 25A Iout



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                                              LM3475
Drag-Select for Table Reset Graph
Also Recommended
LM1770▲Low-Voltage SOT-23 Synchronous Buck Controller
LM1771▲Low-Voltage Synchronous Buck Controller With Precision Enable
LM2743▲Sync Buck Controller - 2A To 25A Iout

Typical Application
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Block Diagram
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Typical Performance
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Paramaters / ValuesLM3475 LM1770 LM1771 LM2743
Output Current5000 mA 4000 mA 6000 mA 20000 mA
Input Min Voltage2.7 Volt 2.8 Volt 2.8 Volt 1 Volt
Input Max Voltage10 Volt 5.5 Volt 5.5 Volt 16 Volt
Output Range0.8V to Vin 0.8V to 4.5V 0.8V to 4.5V 0.6V to 13.5V
Frequency Min0 kHz 300 kHz 300 kHz 50 kHz
Frequency Max1400 kHz 1000 kHz 1000 kHz 2000 kHz
Feedback Voltage0.8 Volt 0.8 Volt 0.8 Volt 0.6 Volt
Feedback Tolerance1.5 % 2 % 2 %
Efficiency (peak)90 % 95 % 95 % 85 %
Adj Switch FrequencyNo No No Yes
Adjustable OutputYes Yes Yes Yes
On/Off PinYes No Yes Yes
Error FlagNo No No Yes
SoftStartYes Yes Yes Yes
Sync PinNo No No No
InvertingNo Yes No No
FlybackNo No No No
Lossless Current SenseYes No No Yes
RegTypeSwitching Controller Switching Controller Switching Controller Switching Controller
Temperature Min-40 deg C -40 deg C -40 deg C -40 deg C
Temperature Max125 deg C 125 deg C 125 deg C 125 deg C
Channels1 Channels 1 Channels 1 Channels 1 Channels
Special FeaturesFast transient response; High efficiency; Wide Vin range; 100% duty cycle capable No compensation required Precision enable for sequencing multiple rails 2.7V UVLO; Tri-State output during SD; Tracking; Precision SD threshold
TopologyBuck Buck Buck Buck
PWM ModeHysteretic Constant on-time Constant on-time Voltage
Step-DownYes No Yes Yes
Step-UpNo No No No
Output Max1 Volt 4.5 Volt 4.5 Volt 13.5 Volt
Output Min0.8 Volt 0.8 Volt 0.8 Volt 0.6 Volt

Datasheet
TitleSizeDateOther
Language
LM3475 Hysteretic PFET Buck Controller777
Kbytes		7-Jan-05 


Featured Application Notes
TitleSizeDateOther
Language
AN-1381: Application Note 1381 LM3475 Evaluation Board457
Kbytes		4-May-05 


More Application Notes
TitleSizeDateOther
Language
AN-1204: Application Note 1204 LM3478/LM3488 Evaluation Board218
Kbytes		10-May-04 
AN-1149: Application Note 1149 Layout Guidelines for Switching Power Supplies248
Kbytes		1-May-04日本語
AN-1193: Application Note 1193 LM3477 Evaluation Board248
Kbytes		10-May-04 
AN-1286: Application Note 1286 Compensation For The LM3478 Boost Controller204
Kbytes		19-May-09日本語
中文
AN-1484: Application Note 1484 Designing A SEPIC Converter196
Kbytes		30-Apr-08日本語
中文

Part Number(s)
(NSID)		Top ViewAvailabilityCurrent Reported StockBudgetary PricingStandard Pack Size
LM3475MF/NOPB
LM3475MF

RoHS



SOT-23		Full production
Lead Time: 6 weeks

Samples
DistributorRegionQty
ARROWWorldwide655
AVNET-EMWorldwide2000
DIGIKEYWorldwide3409
FARNELLEurope and Asia1900
FUTUREWorldwide1100
KEIKONGAsia Pacific1000
NEWARKAmericas75
RS COMPONENTSWorldwide690
TECHMOSAAsia Pacific15000
$0.52 each at 1K+ pcsreel
of
1000
LM3475MFX/NOPB

RoHS



SOT-23		Full production
Lead Time: 6 weeks

 
DistributorRegionQty
DIGIKEYWorldwide0
TECHMOSAAsia Pacific69000
$0.52 each at 1K+ pcsreel
of
3000

Part Number(s)
(NSID)		DescriptionAvailabilityCurrent Reported StockBudgetary PricingStandard Pack Size
LM3475EVAL
Hysteretic PFET Buck ControllerFull production
Lead Free (RoHS)

 
DistributorRegionQty
DIGIKEYWorldwide0
NATIONALWorldwide45
$29.40 each1
LM3475 Hysteretic PFET Buck Controller

General Features:
  • Easy to use control methodology
  • 0.8V to VIN adjustable output range
  • High Efficiency (90% typical)
  • ±0.9% (±1/5% over temp) feedback voltage
  • 100% duty cycle capable
  • Maximum operating frequency up to 2MHz
  • Internal Soft-Start
  • Enable pin
  • SOT23-5 package
Applications:
  • TFT Monitor
  • Auto PC
  • Vehicle Security
  • Navigation Systems
  • Notebook Standy Supply
  • Battery Powered Portable Applications
  • Distributed Power Systems
LM3475 EVAL Pitchpak includes:
  • A fully assembled LM3475 evaluation board,
  • LM3475 datasheet
  • LM3475 eval board appnote

Part Number(s)
(NSID)		Top ViewTypePinsMSL RatingPeak ReflowRoHSCAD SymbolsModelsPackage
Marking
Format
LM3475MF/NOPB
LM3475MF
SOT-2351
1		260
260		RoHSDownloadN/A
S65B
XTT
LM3475MFX/NOPB
SOT-2351260RoHSDownloadN/A
S65B
XTT

Reliability Metrics
Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM3475MFABCD15003417500423400011201409060
LM3475MFXABCD15003417500423400011201409060

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.


[Information as of 21-Nov-2009]