LT3825
Isolated No-Opto Synchronous Flyback Controller with Wide Input Supply Range
Top
Overview
Features and Benefits
- Senses Output Voltage Directly from Primary Side Winding—No Opto-Isolator Required
- Synchronous Driver for High Efficiency
- Input Voltage Limited Only by External Power Components
- Accurate Output Regulation without User Trims
- Switching Frequency from 50kHz to 250kHz
- Synchronizable
- Load Compensation
- Programmable Undervoltage Lockout
- Available in a Thermally Enhanced 16-Lead TSSOP Package
Product Details
The LT3825 is an isolated switching regulator controller designed for medium power flyback topologies. A typical application is 10W to 60W with input voltage limited only by external power path components. A third transformer winding provides output voltage feedback.
The LT3825 is a current mode controller that regulates output voltage based on sensing secondary voltage via a transformer winding during flyback. This allows for tight output regulation without the use of an opto-isolator, improving dynamic response and reliability. Synchronous rectification increases converter efficiency and improves output cross regulation in multiple output converters.
The LT3825 operates in forced continuous conduction mode which improves cross regulation in multiple winding applications. Switching frequency is user programmable and can be externally synchronized. The part also has load compensation, undervoltage lockout and soft-start circuity.
Applications
- Isolated Medium Power (10W to 60W) Supplies
- Isolated Telecom, Medical Converters
- Instrumentation Power Supplies
- Isolated Power over Ethernet Supplies
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 (6)
Documentation & Resources
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R458 Reliability Data3/22/2018PDF31 K
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DC894C-C - Demo Manual2/10/2014PDF577K
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DC894C-B - Demo Manual2/10/2014PDF1M
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DC894B-C - Demo Manual10/7/2011PDF542K
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DC894A-A - Demo Manual10/15/2009PDF1M
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DC950A - Demo Manual9/24/2009PDF345K
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DC1143A - Demo Manual9/24/2009PDF325K
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DN1011 - Simple High Efficiency Isolated Flyback Supply Without Optoisolator8/22/2007PDF104K
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:
LT3825
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 |
|---|---|---|---|---|
| LT3825EFE#PBF | Material Declaration | Reliability Data | 16-Lead TSSOP w/ EP | |
| LT3825EFE#TRPBF | Material Declaration | Reliability Data | 16-Lead TSSOP w/ EP | |
| Wafer Fabrication Data | R458 Reliability Data |
PCN-PDN Information
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Sample & Buy
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Buy Now Pricing
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List Pricing
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Lead Times
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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.