Features and Benefits
- High-Speed Top and Bottom Gate Drivers for
- 2-Switch Forward Converter
- On-Chip Rectifier and Self-Starting Architecture
- Eliminate Need for Separate Gate Drive Bias Supply
- Wide Input Voltage Supply Range: 18V to 80V
- Tolerant of 100V Input Voltage Transients
- Linear Regulator Controller for Fast Start-Up
- Precision UVLO with Adjustable Hysteresis
- Overcurrent Protection
- Volt-Second Limit Prevents Transformer Core Saturation
- Voltage Feedforward for Fast Transient Response
- Available in 16-Lead Narrow SSOP Package
The LTC3705 is a controller for a 2-switch forward converter and includes on-chip bottom and top gate drivers that do not require external transformers. For secondary-side control, combine the LTC3705 with the LTC3706 PolyPhase® secondary-side synchronous forward controller to create a complete forward converter using a minimum of discrete parts. A proprietary scheme is used to multiplex gate drive signals across the isolation barrier through a tiny pulse transformer. The on-chip rectifier and the same pulse transformer provide gate drive bias power.
Alternatively, the LTC3705 can be used as a standalone voltage mode controller in a primary-side control architecture with optoisolator feedback. Voltage feedforward provides excellent line regulation and transient response.
- Isolated 48V Telecommunication Systems
- Internet Servers and Routers
- Distributed Power Step-Down Converters
- Automotive and Heavy Equipment
Product Lifecycle Not Recommended for New Designs
This designates products ADI does not recommend broadly for new designs.
Evaluation Kits (1)
Demonstration circuit 776 is a 36V-72VIN, 2-switch forward converter with synchronous secondary-side control featuring the LTC3705 and LTC3706. This circuit was designed specifically to attain a high stepdown ratio power supply in one stage in order to efficiently power 1.5V loads from a typical telecom input voltage range. Isolation voltage is 1500VDC. This circuit features secondary-side control of the supply without the need of an optocoupler.
Tools & Simulations
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.
Models for the following parts are available in LTspice:
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.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.
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.