LT1931 - 1.2MHz/2.2MHz Inverting DC/DC Converters in ThinSOT

Features

  • 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

LT1931 Typical Application
LT1931 Typical Application

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.

Packaging

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

SOT-23

LT1931 Package Drawing

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.

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
DC383B LTC1930ES5/LTC1931ES5 Demo Board | 3 Circuits: Boost/SEPIC/Inverter, 5Vin to 12Vout1@300mA, 10V-16Vin to 12Vout2@300mA, 12Vin to -12Vout3@350mA $75.00
DC397A LT1930AES5/LT1931AES5 Demo Board | 3 Circuits: Boost/SEPIC/Inverter: 5Vin to 12Vout1@250mA, 10V-16Vin to 12Vout2@250mA, 12Vin to -12Vout3@250mA $75.00
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Click here to view our complete list of demo boards

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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Design Tools

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Models for the following parts are available in LTspice IV:
LT1931
LT1931A

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