LT3825
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LT3825

Isolated No-Opto Synchronous Flyback Controller with Wide Input Supply Range

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Info: : PRODUCTION tooltip
Info: : PRODUCTION tooltip
Part Details
Part Models 2
1ku List Price Starting From $3.72
Features
  • 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
Additional Details
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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
Part Models 2
1ku List Price Starting From $3.72

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Documentation

Documentation

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
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Product Lifecycle

PCN

Apr 6, 2022

- 22_0068

Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL

LT3825EFE#PBF

PRODUCTION

LT3825EFE#TRPBF

PRODUCTION

Filter by Model

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Part Models

Product Lifecycle

PCN

Apr 6, 2022

- 22_0068

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Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL

LT3825EFE#PBF

PRODUCTION

LT3825EFE#TRPBF

PRODUCTION

Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 6

reference details image

DC1143A

LT3825EFE Demo Board | Synchronous Isolated Flyback, 36V ≤ VIN ≤ 72V, VOUT: 3.3V @ 6A

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DC1143A

LT3825EFE Demo Board | Synchronous Isolated Flyback, 36V ≤ VIN ≤ 72V, VOUT: 3.3V @ 6A

LT3825EFE Demo Board | Synchronous Isolated Flyback, 36V ≤ VIN ≤ 72V, VOUT: 3.3V @ 6A

Product Detail

Demonstration circuit 1143 is a 20W isolated flyback converter with synchronous rectification and primary-side regulation featuring the LT3825. The circuit was designed to demonstrate the high levels of performance, efficiency and small solution size attainable using this part in a flyback power supply. It operates at 250kHz and produces a regulated 3.3V, 6A output from an input voltage range of 36V to 72V: suitable for telecom and other applications. It has a footprint area that is 1.0 inch square. Synchronous rectification helps to attain efficiency exceeding 88%. Isolation voltage is 1500VDC.



reference details image

DC894C-B

LT3825EFE Isolated Demo Board | Synchronous Flyback Controller, 36V ≤ VIN ≤ 72V; VOUT = 5V @ 8A

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DC894C-B

LT3825EFE Isolated Demo Board | Synchronous Flyback Controller, 36V ≤ VIN ≤ 72V; VOUT = 5V @ 8A

LT3825EFE Isolated Demo Board | Synchronous Flyback Controller, 36V ≤ VIN ≤ 72V; VOUT = 5V @ 8A

Product Detail

Demonstration circuit 894C-B is a 36V-72Vin, synchronous flyback converter featuring the LT3825. The circuit was designed specifically to attain a high current, low ripple, synchronously rectified flyback to efficiently power 5.0V loads at up to 8A from a typical telecom input voltage range.

reference details image

DC894B-C

LT3825EFE Demo Board | Isolated, 36V ≤ VIN ≤ 72V, VOUT = 12V @ 5A

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DC894B-C

LT3825EFE Demo Board | Isolated, 36V ≤ VIN ≤ 72V, VOUT = 12V @ 5A

LT3825EFE Demo Board | Isolated, 36V ≤ VIN ≤ 72V, VOUT = 12V @ 5A

Product Detail

Demonstration circuit 894B-C is a 36V-72Vin, synchronous flyback converter featuring the LT3825. This circuit was designed specifically to attain a high current, low ripple, synchronously rectified flyback to efficiently power 12V loads at up to 5A from a typical telecom input voltage range. This circuit features synchronous rectifier drive outputs, output voltage regulation without the need of an optocoupler, self-starting architecture and input undervoltage lockout.

reference details image

DC894C-C

LT3825EFE Isolated Demo Board | Synchronous No Opto Flyback Controller, 36V ≤ VIN ≤ 72V; VOUT = 12V @ 5A

zoom

DC894C-C

LT3825EFE Isolated Demo Board | Synchronous No Opto Flyback Controller, 36V ≤ VIN ≤ 72V; VOUT = 12V @ 5A

LT3825EFE Isolated Demo Board | Synchronous No Opto Flyback Controller, 36V ≤ VIN ≤ 72V; VOUT = 12V @ 5A

Product Detail

Demonstration circuit 894C-C is a 36V-72VIN, synchronous flyback converter featuring the LT3825. This circuit was designed specifically to attain a high current, low ripple, synchronously rectified flyback to efficiently power 12V loads at up to 5A from a typical telecom input voltage range. This circuit features synchronous rectifier drive outputs, output voltage regulation without the need of an optocoupler, self-starting architecture and input undervoltage lockout.

reference details image

DC894A-A

LT3825EFE Demo Board I Synchronous Flyback Converter, VIN = 36V to 72V, VOUT = 3.3V @ 12A

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DC894A-A

LT3825EFE Demo Board I Synchronous Flyback Converter, VIN = 36V to 72V, VOUT = 3.3V @ 12A

LT3825EFE Demo Board I Synchronous Flyback Converter, VIN = 36V to 72V, VOUT = 3.3V @ 12A

Product Detail

Demonstration circuit 894A-A is a 36V-72VIN, synchronous flyback converter featuring the LT3825. This circuit was designed specifically to attain a high current, low ripple, synchronously rectified flyback to efficiently power 3.3V loads at up to 12A from a typical telecom input voltage range. This circuit features synchronous rectifier drive outputs, output voltage regulation without the need of an optocoupler, a self-starting architecture and input undervoltage lockout.

reference details image

DC950A-A

LT3825EFE Demo Board | Isolated Synchronous Flyback, 36V ≤ VIN ≤ 72V, VOUT: 5V/2A, 3.3V/3A, 2.5V/3A

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DC950A-A

LT3825EFE Demo Board | Isolated Synchronous Flyback, 36V ≤ VIN ≤ 72V, VOUT: 5V/2A, 3.3V/3A, 2.5V/3A

LT3825EFE Demo Board | Isolated Synchronous Flyback, 36V ≤ VIN ≤ 72V, VOUT: 5V/2A, 3.3V/3A, 2.5V/3A

Product Detail

Demonstration circuit 950A-A is an isolated, 30W multi-output, synchronous flyback converter in 1/8 brick format featuring the LT3825. Output voltage sensing is implemented without the use of opto-coupler, by sensing the voltage across a primary side auxiliary winding. A load compensation circuit is used to compensate for voltage drops caused by load currents. DC950A-A has input voltage range 36V-72V and features the LT3825. Demonstration circuit 950A uses a transformer design with tapped secondary winding, to achieve higher efficiency and better cross regulation than is possible with a transformer that uses a separate winding for each output.



Tools & Simulations

Tools & Simulations 1

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.

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