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LT1931: 1.2MHz/2.2MHz Inverting DC/DC Converters in ThinSOT Data Sheet2/3/2010PDF448K
Overview
Features and Benefits
- Fixed Frequency 1.2MHz/2.2MHz Operation
- Very Low Noise: 1mVP-P Output Ripple
- –5V at 350mA from 5V Input
- –12V at 150mA from 5V Input
- Uses Small Surface Mount Components
- Wide Input Range: 2.6V to 16V
- Low Shutdown Current: <1µA
- Low VCESAT Switch: 400mV at 1A
- Pin-for-Pin Compatible with the LT1611
- Low Profile (1mm) ThinSOT™ Package
Product Details
The LT1931/LT1931A are the industry’s highest power inverting SOT-23 current mode DC/DC converters. Both parts include a 1A integrated switch allowing high current outputs to be generated in a small footprint. The LT1931 switches at 1.2MHz while the LT1931A switches at 2.2MHz. These high speeds enable the use of tiny, low cost capacitors and inductors 2mm or less in height. The LT1931 is capable of generating –5V at 350mA or –12V at 150mA from a 5V supply, while the LT1931A can generate –5V at 300mA using significantly smaller inductors. Both parts are easy pin-for-pin upgrades for higher power LT1611 applications.The LT1931/LT1931A operate in a dual inductor inverting topology that filters both the input side and output side current. Very low output voltage ripple approaching 1mVP-P can be achieved when ceramic output capacitors are used. Fixed frequency switching ensures a clean output free from low frequency noise typically present with charge pump solutions. The low impedance output remains within 1% of nominal during large load steps. The 36V switch allows VIN to VOUT differential of up to 34V.
The LT1931/LT1931A are available in the 5-lead ThinSOT package.
Applications
- Disk Drive MR Head Bias
- Digital Camera CCD Bias
- LCD Bias
- GaAs FET Bias
- Local Low Noise/Low Impedance Negative Supply
Product Categories
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Documentation & Resources
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R303 Reliability Data3/23/2018PDF232 K
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DC383B - Demo Manual5/17/2010PDF736K
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DC397A - Demo Manual9/24/2009PDF484K
Tools & Simulations
LTspice
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

Models for the following parts are available in LTspice:
Reference Designs (4)
Design Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
Part Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
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LT1931AES5#TRMPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
LT1931AES5#TRPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
LT1931AIS5#TRMPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
LT1931AIS5#TRPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
LT1931ES5#TRMPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
LT1931ES5#TRPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
LT1931IS5#TRMPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
LT1931IS5#TRPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
Wafer Fabrication Data | R303 Reliability Data |
Sample & Buy
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.