LT1611 - Inverting 1.4MHz Switching Regulator in 5-Lead SOT-23

Features

  • Very Low Noise: 1mVP–P Output Ripple
  • –5V at 150mA from a 5V Input
  • Better Regulation Than a Charge Pump
  • Effective Output Impedance: 0.14Ohms
  • Uses Tiny Capacitors and Inductors
  • Internally Compensated
  • Fixed Frequency 1.4MHz Operation
  • Low Shutdown Current: <1µA
  • Low VCESAT Switch: 300mV at 300mA
  • Tiny 5-Lead SOT-23 Package

Typical Application

LT1611 Typical Application
LT1611 Typical Application

Description

The LT1611 is the industry’s first inverting 5-lead SOT-23 current mode DC/DC converter. Intended for use in small, low power applications, it operates from an input voltage as low as 1.1V and switches at 1.4MHz, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. Its small size and high switching frequency enable the complete DC/DC converter function to consume less than 0.25 square inches of PC board area. Capable of generating –5V at 150mA from a 5V supply or –5V at 100mA from a 3V supply, the LT1611 replaces nonregulated “charge pump” solutions in many applications.

The LT1611 operates in a dual inductor inverting topology which filters the input side as well as the output side of the DC/DC converter. Fixed frequency switching ensures a clean output free from low frequency noise typically present with charge pump solutions. No load quiescent current of the LT1611 is 3mA, while in shutdown quiescent current drops to 0.5µA. The 36V switch allows VIN to VOUT differential of up to 33V.

The LT1611 is available in the 5-lead SOT-23 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
LT1611CS5#PBF SOT-23 S5 C 05-08-1635 Yes
LT1611CS5#TRMPBF SOT-23 S5 C 05-08-1635 Yes
LT1611CS5#TRPBF SOT-23 S5 C 05-08-1635 Yes


LT1611 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
LT1611CS5#PBF SOT-23 C $2.46 Yes
LT1611CS5#TRMPBF SOT-23 C $2.46 $2.02 Yes
LT1611CS5#TRPBF SOT-23 C $2.46 $2.00 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.

Click here to view our complete list of demo boards

Applications

  • MR Head Bias
  • Digital Camera CCD Bias
  • LCD Bias
  • GaAs FET Bias
  • Positive-to-Negative Conversion

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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

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
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Models for the following parts are available in LTspice:
LT1611

Technical Support