Overview
Features and Benefits
- Works with DCM and BCM/CrCM Conduction Mode Flyback Topologies
- VCC: 4.5V to 40V
- Supports Up to 150V MOSFETs
- 26ns Turn-Off Propagation Delay
- Accurate Minimum On and Off Timers for Reliable Operation
- Adjustable and Accurate Trip Point: +5mV to –30mV
- 1Ω Gate Driver Pull-Down
- SOT-23 5-Lead Package
Product Details
The LT8309 is a secondary-side synchronous rectifier driver that replaces the output rectifier diode in a flyback topology. By replacing the diode with a N-channel MOSFET, applications are no longer restricted by the heat constraints of the output diode. The IC replicates the behavior of a diode by sensing the drain-to-source voltage to determine when the current becomes negative. The LT8309's low minimum on- and off-times help improve noise immunity.
The fast propagation delay of 26ns allows applications to operate in discontinuous conduction mode (DCM) and critical conduction mode (CrCM). The gate driver features a 0.8Ω pull-down device for fast turn-offs. The 40V VCC rating allows the part to be driven from the output voltage or the rectified drain voltage of the MOSFET. A low quiescent current of 400μA maximizes efficiency at low output currents.
Applications
- High Output Current Flybacks
- High Efficiency Flybacks
Product Categories
Markets and Technologies
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
-
R570 Reliability Data3/23/2018
-
DC1961A - Demo Manual2/24/2014
-
No-Opto Isolated Flyback Converters7/13/2017
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Isolated Power Your Way1/21/2014
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:
LT8309
Product Recommendations
LT8309 Companion Parts
Recommended Related 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 |
|---|---|---|---|---|
| LT8309ES5#TRMPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
| LT8309ES5#TRPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
| LT8309HS5#TRMPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
| LT8309HS5#TRPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
| LT8309IS5#TRMPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
| LT8309IS5#TRPBF | Material Declaration | Reliability Data | 5-Lead TSOT-23 | |
| Wafer Fabrication Data | R570 Reliability Data |
PCN-PDN Information
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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.