LTC1474 - Low Quiescent Current High Efficiency Step-Down Converters

Features

  • High Efficiency: Over 92% Possible
  • Very Low Standby Current: 10µA Typ
  • Available in Space Saving 8-Lead MSOP Package
  • Internal 1.4ohms Power Switch (VIN = 10V)
  • Wide VIN Range: 3V to 18V Operation
  • Very Low Dropout Operation: 100% Duty Cycle
  • Low-Battery Detector Functional During Shutdown
  • Programmable Current Limit with Optional Current Sense Resistor (10mA to 400mA)
  • Short-Circuit Protection
  • Few External Components Required
  • Active Low Micropower Shutdown: IQ = 6µA Typ
  • Pushbutton On/Off (LTC1475 Only)
  • 3.3V, 5V and Adjustable Output Versions

Typical Application

LTC1474 Typical Application
LTC1474 Typical Application

Description

The LTC1474/LTC1475 series are high efficiency step-down converters with internal P-channel MOSFET power switches that draw only 10µA typical DC supply current at no load while maintaining output voltage. The LTC1474 uses logic-controlled shutdown while the LTC1475 features push button on/off.

The low supply current coupled with Burst Mode operation enables the LTC1474/LTC1475 to maintain high efficiency over a wide range of loads. These features, along with their capability of 100% duty cycle for low dropout and wide input supply range, make the LTC1474/LTC1475 ideal for moderate current (up to 300mA) battery-powered applications.

The peak switch current is user-programmable with an optional sense resistor (defaults to 325mA minimum if not used) providing a simple means for optimizing the design for lower current applications. The peak current control also provides short-circuit protection and excellent start-up behavior. A low-battery detector that remains functional in shutdown is provided .

The LTC1474/LTC1475 series availability in 8-lead MSOP and SO packages and need for few additional components provide for a minimum area solution.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LTC1474CMS8-3.3#PBF MS-8 MS8 C 05-08-1660 Yes
LTC1474CMS8-3.3#TRPBF MS-8 MS8 C 05-08-1660 Yes
LTC1474CMS8-5#PBF MS-8 MS8 C 05-08-1660 Yes
LTC1474CMS8-5#TRPBF MS-8 MS8 C 05-08-1660 Yes
LTC1474CMS8#PBF MS-8 MS8 C 05-08-1660 Yes
LTC1474CMS8#TRPBF MS-8 MS8 C 05-08-1660 Yes
LTC1474CS8-3.3#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1474CS8-3.3#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1474CS8-5#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1474CS8-5#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1474CS8#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1474CS8#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1474IS8-3.3#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LTC1474IS8-3.3#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes
LTC1474IS8-5#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LTC1474IS8-5#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes
LTC1474IS8#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LTC1474IS8#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes


LTC1474 Package Drawing
LTC1474 Package Drawing
LTC1474 Package Drawing
LTC1474 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC1474CMS8-3.3#PBF MS-8 C $4.60 $3.75 Yes
LTC1474CMS8-3.3#TRPBF MS-8 C $3.81 Yes
LTC1474CMS8-5#PBF MS-8 C $4.60 $3.75 Yes
LTC1474CMS8-5#TRPBF MS-8 C $3.81 Yes
LTC1474CMS8#PBF MS-8 C $4.60 $3.75 Yes
LTC1474CMS8#TRPBF MS-8 C $3.81 Yes
LTC1474CS8-3.3#PBF SO-8 C $3.95 $3.40 Yes
LTC1474CS8-3.3#TRPBF SO-8 C $3.46 Yes
LTC1474CS8-5#PBF SO-8 C $3.95 $3.40 Yes
LTC1474CS8-5#TRPBF SO-8 C $3.46 Yes
LTC1474CS8#PBF SO-8 C $3.95 $3.40 Yes
LTC1474CS8#TRPBF SO-8 C $3.46 Yes
LTC1474IS8-3.3#PBF SO-8 I $5.10 $4.15 Yes
LTC1474IS8-3.3#TRPBF SO-8 I $4.21 Yes
LTC1474IS8-5#PBF SO-8 I $5.10 $4.15 Yes
LTC1474IS8-5#TRPBF SO-8 I $4.21 Yes
LTC1474IS8#PBF SO-8 I $5.10 $4.15 Yes
LTC1474IS8#TRPBF SO-8 I $4.21 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC143A-A LTC1474CMS8 | LOW Q-CURRENT HIGH EFFICIENCY SWITCHING REGULATOR, 3.3V ADJ @ 300mA $100.00
DC143A-C LTC1474CMS8-5 | LOW Q-CURRENT HIGH EFFICIENCY SWITCHING REGULATOR, 5V FIXED @ 300mA $100.00
Buy Now
Click here to view our complete list of demo boards

Applications

  • Cellular Telephones and Wireless Modems
  • 4mA to 20mA Current Loop Step-Down Converter
  • Portable Instruments
  • Battery-Operated Digital Devices
  • Battery Chargers
  • Inverting Converters
  • Intrinsic Safety Applications

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC1474
LTC1474-3.3
LTC1474-5

Technical Support