Overview
Features and Benefits
- Wide Input Range: 3V to 25V
- Short-Circuit Protected Over Full Input Range
- 2A Output Current Capability
- Adjustable/Synchronizable Fixed Frequency Operation from 250kHz to 2.2MHz
- Soft-Start/Tracking Capability
- Output Adjustable Down to 0.8V
- Adjustable Linear Regulator/Driver with 13mA Output Capability
- Power Good Comparator with Complementary Outputs
- Low Shutdown Current: 12μA
- Thermally Enhanced 3mm × 3mm DFN Package
Product Details
The LT1939 is a current mode PWM step-down DC/DC converter with an internal 2.3A switch. The wide input range of 3V to 25V makes the LT1939 suitable for regulating power from a wide variety of sources, including automotive batteries, industrial supplies and unregulated wall adapters.
Resistor-programmable 250kHz to 2.2MHz frequency range and synchronization capability enable optimization between efficiency and external component size. Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protection against a shorted output. The soft-start feature controls the ramp rate of the output voltage, eliminating input current surge during start-up, and also provides output tracking.
The LT1939 contains an internal NPN transistor with feedback control which can be configured as a linear regulator or as a linear regulator controller.
The LT1939’s low current shutdown mode (<12μA) enables easy power management in battery-powered systems.
Applications
- Automotive Battery Regulation
- Industrial Control
- Wall Transformer Regulation
- Distributed Power Regulation
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 (1)
Documentation & Resources
-
R530 Reliability Data3/26/2018
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DC1293A - Demo Manual9/24/2009
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36Vin Multichannel Bucks8/18/2016
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:
LT1939
Product Recommendations
LT1939 Companion Parts
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 |
|---|---|---|---|---|
| LT1939EDD#PBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| LT1939EDD#TRPBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| LT1939IDD#PBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| LT1939IDD#TRPBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| Wafer Fabrication Data | R530 Reliability Data |
Support & Discussions
Sample & Buy
Ordering FAQs
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Buy Now Pricing
(**) Displayed Buy Now Price and Price Range is based on small quantity orders.
List Pricing
(*)The 1Ku 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 Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
Lead Times
Please see the latest communication from our CCO regarding lead times.
Sampling
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Evaluation Boards
Pricing displayed is based on 1-piece.
Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.
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.