LTC1911 - Low Noise, High Efficiency, Inductorless Step-Down DC/DC Converter

Features

  • Low Noise Constant Frequency Operation
  • 2.7V to 5.5V Input Voltage Range
  • No Inductors
  • Typical Efficiency 25% Higher Than LDOs
  • Shutdown Disconnects Load from VIN
  • Output Voltage: 1.8V ±4% or 1.5V ±4%
  • Output Current: 250mA
  • Low Operating Current: IIN = 180µA Typ
  • Low Shutdown Current: IIN = 10µA Typ
  • Oscillator Frequency: 1.5MHz
  • Soft-Start Limits Inrush Current at Turn On
  • Short-Circuit and Overtemperature Protected
  • Available in an 8-Pin MSOP Package

Typical Application

LTC1911 Typical Application
LTC1911 Typical Application

Description

The LTC1911 is a switched capacitor step-down DC/DC converter that produces a 1.5V or 1.8V regulated output from a 2.7V to 5.5V input. The part uses switched capacitor fractional conversion to achieve high efficiency over the entire input range. No inductors are required. Internal circuitry controls the step-down conversion ratio to optimize efficiency as the input voltage and load conditions vary. Typical efficiency is over 25% higher than that of a linear regulator.

A unique constant frequency architecture provides a low noise regulated output as well as lower input noise than conventional charge pump regulators. High frequency operation (fOSC = 1.5MHz) simplifies output filtering to further reduce conducted noise. To optimize efficiency,the part enters Burst Mode’ operation under light load conditions.

 

Low operating current (180µA with no load, 10µA in shutdown) and low external parts count (two 1µF flying capacitors and two 10µF bypass capacitors) make theLTC1911 ideally suited for space constrained battery powered applications. The part is short-circuit and over temperature protected, and is available in an 8-pin MSOP package.

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
LTC1911EMS8-1.5#PBF MS-8 MS8 E 05-08-1660 Yes
LTC1911EMS8-1.5#TRPBF MS-8 MS8 E 05-08-1660 Yes
LTC1911EMS8-1.8#PBF MS-8 MS8 E 05-08-1660 Yes
LTC1911EMS8-1.8#TRPBF MS-8 MS8 E 05-08-1660 Yes


LTC1911 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
LTC1911EMS8-1.5#PBF MS-8 E $2.77 $2.34 Yes
LTC1911EMS8-1.5#TRPBF MS-8 E $2.40 Yes
LTC1911EMS8-1.8#PBF MS-8 E $2.77 $2.34 Yes
LTC1911EMS8-1.8#TRPBF MS-8 E $2.40 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
DC342A-A LTC1911EMS8-1.8 | Low Noise, Constant Frequency Step-Down Charge Pump Contact Factory
DC342A-B LTC1911EMS8-1.5 | Low Noise, Constant Frequency Step-Down Charge Pump Contact Factory
Buy Now
Click here to view our complete list of demo boards

Applications

  • Handheld Computers
  • Cellular Phones
  • Smart Card Readers
  • Portable Electronic Equipment
  • Handheld Medical Instruments
  • Low Power DSP Supplies

Product Notifications

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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:
LTC1911-1.5
LTC1911-1.8

Technical Support