LT1931A - 1.2MHz/2.2MHz Inverting DC/DC Converters in ThinSOT

Features

  • Click Here For LT1931 Evaluation Kits
  • 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

Typical Application

LT1931A
LT1931A
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Description

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.

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Packaging

ThinSOT

LT1931A
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Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT1931AES5 SOT 5 E $2.46   View
LT1931AES5#PBF SOT 5 E $2.46   View
LT1931AES5#TR SOT 5 E $2.46 $2.06 View
LT1931AES5#TRM SOT 5 E $2.46 $2.08 View
LT1931AES5#TRMPBF SOT 5 E $2.46 $2.08 View
LT1931AES5#TRPBF SOT 5 E $2.46 $2.06 View
LT1931AIS5 SOT 5 I $3.07   View
LT1931AIS5#PBF SOT 5 I $3.07   View
LT1931AIS5#TR SOT 5 I $3.07 $2.16 View
LT1931AIS5#TRM SOT 5 I $3.07 $2.18 View
LT1931AIS5#TRMPBF SOT 5 I $3.07 $2.18 View
LT1931AIS5#TRPBF SOT 5 I $3.07 $2.16 View
LT1931ES5 SOT 5 E $2.46   View
LT1931ES5#PBF SOT 5 E $2.46   View
LT1931ES5#TR SOT 5 E $2.46 $2.06 View
LT1931ES5#TRM SOT 5 E $2.46 $2.08 View
LT1931ES5#TRMPBF SOT 5 E $2.46 $2.08 View
LT1931ES5#TRPBF SOT 5 E $2.46 $2.06 View
LT1931IS5 SOT 5 I $3.07   View
LT1931IS5#PBF SOT 5 I $3.07   View
LT1931IS5#TR SOT 5 I $3.07 $2.16 View
LT1931IS5#TRM SOT 5 I $3.07 $2.18 View
LT1931IS5#TRMPBF SOT 5 I $3.07 $2.18 View
LT1931IS5#TRPBF SOT 5 I $3.07 $2.16 View
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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.

Evaluation Kits

Part Number Description Price
DC383B LTC1930ES5/LTC1931ES5 Demo Board | 1.2 MHz, DC/DC Converter  
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Applications

  • Disk Drive MR Head Bias
  • Digital Camera CCD Bias
  • LCD Bias
  • GaAs FET Bias
  • Local Low Noise/Low Impedance Negative Supply
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Simulate

LTSpice / SwitcherCAD III is a powerful FREE circuit simulator and schematic capture program, providing macro models for 80% of Linear Technology's switching regulators, over 200 op amp models, as well as resistors, transistors and MOSFET models.

  • Step 1. If you do not already have a copy of LTSpice, click here to download and install LTSpice / SwitcherCAD III

  • Step 2. Once LTSpice is installed, click here for a ready to run  demonstration circuit of the LT1931A.

  • Step 3. If LTspice / SwitcherCAD III does not automatically open after clicking the above link, 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 demonstartion circuit by selecting "Open" from the "File" menu.
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