LM3475 - Hysteretic PFET Buck Controller
Datasheet Packaging Samples & Pricing Eval. Boards Reliability Reference Designs Application Notes Knowledge Base

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

General 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. More...


Applications


TFT Monitor
Auto PC
Vehicle Security
Navigation Systems
Notebook Standby Supply
Battery Powered Portable Applications
Distributed Power Systems
  Typical Application
click for larger image


ParametersValues
Output Current 5000 mA
Input Min Voltage 2.7 Volt
Input Max Voltage 10 Volt
Output Range 0.8V to Vin
Frequency Min 0 kHz
Frequency Max 1400 kHz
Feedback Voltage 0.8 Volt
Feedback Tolerance 1.5 %
Efficiency (peak) 90 %
Adj Switch Frequency No
Adjustable Output Yes
On/Off Pin Yes
Error Flag No
SoftStart Yes
Sync Pin No
Inverting No
Flyback No
Lossless Current Sense Yes
RegType Switching Controller
Temperature Min -40 deg C
Temperature Max 125 deg C
Channels 1 Channels
Special Features Fast transient response; High efficiency; Wide Vin range; 100% duty cycle capable
Topology Buck
PWM Mode Hysteretic
Step-Down Yes
Step-Up No
Output Max 1 Volt
Output Min 0.8 Volt


Typical Performance


click for larger image


  Also Recommended
LM1770Low-Voltage SOT-23 Synchronous Buck Controller
LM1771Low-Voltage Synchronous Buck Controller With Precision Enable
LM2743Sync Buck Controller - 2A To 25A Iout
Additional Resources
Application Notes


Block Diagram


click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM3475 Hysteretic PFET Buck Controller 777
Kbytes
7-Jan-05 Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.


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
LM3475EVALHysteretic PFET Buck ControllerFull productionN/A
 
Buy Now
1+$29.401-
8 weeksN/A
LM3475MFSOT-235NOPB
STD
1
1
260
260
RoHS Download Full productionN/A
Samples
Buy Now
1K+$0.52reel
of
1000
S65B
XTT
6 weeks2000
LM3475MFXSOT-235NOPB1260RoHS Download Full productionN/A
 
Buy Now
1K+$0.52reel
of
3000
S65B
XTT
6 weeks5000

General 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.

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.



Reference Designs
LM3475 Reference Design - Buck Dual Output Converter: 5V Input, 3.3V @ 2A, 2.5V @ 2A

Application Notes


TitleSize in Kbytes Date Click link below to Download
AN-1381: Application Note 1381 LM3475 Evaluation Board 457
Kbytes
4-May-05 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-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
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]