LT1931

PRODUCTION

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

Part Models: 8
1ku List Price: Starting From $2.56

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Overview

Fixed Frequency 1.2MHz/2.2MHz Operation
Very Low Noise: 1mV_P-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 V_CESAT Switch: 400mV at 1A
Pin-for-Pin Compatible with the LT1611
Low Profile (1mm) ThinSOT^™ Package

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 1mV_P-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 V_IN to V_OUT 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

Part Models: 8
1ku List Price: Starting From $2.56

Documentation

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 Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LT1931AES5#TRMPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT1931AES5#TRPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT1931AIS5#TRMPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT1931AIS5#TRPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT1931ES5#TRMPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT1931ES5#TRPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT1931IS5#TRMPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT1931IS5#TRPBF	5-Lead TSOT-23	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Protection Switches & Controllers 1
LTC4365	RECOMMENDED FOR NEW DESIGNS	Overvoltage, Undervoltage and Reverse Supply Protection Controller

Tools & Simulations

LTspice 2

Models for the following parts are available in LTspice:

LT1931
LT1931A

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.

Evaluation Kits

LTC1930ES5/LTC1931ES5 Demo Board | 3 Circuits: Boost/SEPIC/Inverter, 5VIN to 12VOUT1 @300mA, 10V-16VIN to 12VOUT2 @300mA, 12VIN to -12VOUT3 @350mA

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Product Details

Demonstration Circuit 383B is multipurpose demonstration board featuring the LT1930 and LT1931. The demo board offers three separate DC/DC converters. The Boost circuit is designed to convert a 5V input to 12V output at 300mA maximum load. The SEPIC circuit generates a 12V/300mA output from a 10V~16V variable input. The Inverter circuit is designed for applications requiring -12V/350mA from a positive 12V input.

Resources

DC383B - Demo Manual
5/17/2010

DC383B - Design Files
5/17/2010

DC383B - Schematic
5/17/2010

LT1930AES5/LT1931AES5 Demo Board | 3 Circuits: Boost/SEPIC/Inverter: 5VIN to 12VOUT1 @ 250mA, 10V-16VIN to 12VOUT2 @ 250mA, 12VIN to -12VOUT3 @ 250mA

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Product Details

Demonstration circuit 397 is a multipurpose DC/DC switching regulator using the LT1930A and LT1931A voltage regulators in a SOT-23 package. The demo board offers three separate DC/DC converters for different applications needs. The boost circuit is designed to convert a 5V input to 12V output at 250mA maximum load. The SEPIC circuit generates a constant 12V/250mA (max load) output with a 10V~16V variable input. The inverter circuit is de-signed for applications requiring negative 12V/250mA (max load) from a positive 12V input. All three circuits are designed to demonstrate fast switching frequency (2.2MHz), an internal 36V/1A switch, wide input range, and small circuit size.

Resources

DC397A - Demo Manual
9/24/2009

DC397A - Design File
9/24/2009

DC397A - Schematic
9/24/2009

Reference Designs

Figure 1. CN0577 Simplified Block Diagram

Analog Front End and Digital Interface for Serial LVDS SAR ADCs

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Features and Benefits

18-Bit Resolution, 15 MSPS Data Acquisition System
Arbitrary Voltage Inputs Supported
All Clocking and Power Requirements are Onboard
FMC Connector for FPGA Interfacing

Part Used

Design & Integration Tools

CN0577 Design Files
6.81 M

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Features and Benefits

Analog Devices has worked closely with FPGA and processor manufacturers to develop verified power solutions that optimize cost, size and efficiency in high performance applications
Our reference designs are supported by an intuitive design tool set and IP
Our team can provide designs for quick prototypes that can speed time to market in the most complex applications

Part Used

View Detailed Reference Design

Features and Benefits

Analog Devices has worked closely with FPGA and processor manufacturers to develop verified power solutions that optimize cost, size and efficiency in high performance applications
Our reference designs are supported by an intuitive design tool set and IP
Our team can provide designs for quick prototypes that can speed time to market in the most complex applications

Part Used

View Detailed Reference Design

Features and Benefits

Analog Devices has worked closely with FPGA and processor manufacturers to develop verified power solutions that optimize cost, size and efficiency in high performance applications
Our reference designs are supported by an intuitive design tool set and IP
Our team can provide designs for quick prototypes that can speed time to market in the most complex applications