LT8311
Synchronous Rectifier Controller with Opto-Coupler Driver for Forward Converters
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Overview
Features and Benefits
- Wide Input Supply Range: 3.7V to 30V
- Preactive Mode:
- No Pulse Transformer Required
- DCM Operation at Light Load
- SYNC Mode:
- FCM or DCM Operation at Light Load
- Achieves Highest Efficiency
- 1.5% Feedback Voltage Reference
- 10mA Opto-Coupler Driver
- Output Power Good Indicator
- Integrated Soft-Start Function
Product Details
The LT8311 is used on the secondary side of a forward converter to provide synchronous MOSFET control and output voltage feedback through an opto-coupler. The LT8311’s unique preactive mode allows control of the secondary-side MOSFETs without requiring a traditional pulse transformer for primary- to secondary-side communication. In preactive mode, the output inductor current operates in discontinuous conduction mode (DCM) at light load. If forced continuous mode (FCM) operation is desired at light load, the LT8311 can, alternatively, be used in SYNC mode, where a pulse transformer is required to send synchronous control signals from the primary-side IC to the LT8311.
The LT8311 offers a full featured opto-coupler controller, incorporating a 1.5% reference, a transconductance error amplifier and a 10mA opto-driver. Power good monitoring and output soft-start/overshoot control are also included. The LT8311 is available in a 16-lead FE package with pins removed for high voltage spacing requirements.
Applications
- Offline and HV Car Battery Isolated Power Supplies
- 48V Isolated Power Supplies
- Industrial, Automotive and Military Systems
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 (4)
Documentation & Resources
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R530 Reliability Data3/26/2018
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DC2175A - Demo Manual8/17/2016
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DC1929A - Demo Manual11/30/2015
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DC2015A - Demo Manual11/3/2014
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DC1994A - Demo Manual3/24/2014
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400V+ Active Clamp Forward5/2/2014
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:
LT8311
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 |
|---|---|---|---|---|
| LT8311EFE#PBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| LT8311EFE#TRPBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| LT8311HFE#PBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| LT8311HFE#TRPBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| LT8311IFE#PBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| LT8311IFE#TRPBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| LT8311MPFE#PBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| LT8311MPFE#TRPBF | Material Declaration | Reliability Data | 20-Lead TSSOP w/ EP | |
| Wafer Fabrication Data | R530 Reliability Data |
PCN-PDN Information
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Support & Discussions
LT8311 Discussions
Sample & Buy
Ordering FAQs
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Buy Now Pricing
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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
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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.