LT8309
PRODUCTIONSecondary-Side Synchronous Rectifier Driver
- Part Models
- 6
- 1ku List Price
- Starting From $2.73
Overview
- 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
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
Documentation
Data Sheet 1
User Guide 1
Technical Articles 5
Product Selector Card 1
Brochure 1
Analog Dialogue 2
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 Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| LT8309ES5#TRMPBF | 5-Lead TSOT-23 | ||
| LT8309ES5#TRPBF | 5-Lead TSOT-23 | ||
| LT8309HS5#TRMPBF | 5-Lead TSOT-23 | ||
| LT8309HS5#TRPBF | 5-Lead TSOT-23 | ||
| LT8309IS5#TRMPBF | 5-Lead TSOT-23 | ||
| LT8309IS5#TRPBF | 5-Lead TSOT-23 |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Dec 4, 2019 - 19_0283 LT8309 Data sheet limit change. |
||
| LT8309ES5#TRMPBF | PRODUCTION | |
| LT8309ES5#TRPBF | PRODUCTION | |
| LT8309HS5#TRMPBF | PRODUCTION | |
| LT8309HS5#TRPBF | PRODUCTION | |
| LT8309IS5#TRMPBF | PRODUCTION | |
| LT8309IS5#TRPBF | PRODUCTION | |
|
Apr 11, 2019 - 19_0067 Notification of Wafer Fab Location Change for 0.35 BCD Process |
||
| LT8309ES5#TRMPBF | PRODUCTION | |
| LT8309ES5#TRPBF | PRODUCTION | |
| LT8309HS5#TRMPBF | PRODUCTION | |
| LT8309HS5#TRPBF | PRODUCTION | |
| LT8309IS5#TRMPBF | PRODUCTION | |
| LT8309IS5#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
Can't find the software or driver you need?
Request a Driver/SoftwareHardware Ecosystem
| Parts | Product Life Cycle | Description |
|---|---|---|
| Ideal Diodes and PowerPath Controllers 1 | ||
|
LT4320 LT4320-1 |
Ideal Diode Bridge Controller | |
Tools & Simulations
LTspice 4
- LT3798/LT8309 Demo Circuit - Energy Star Compliant Isolated Converter (85-150VAC to 5V @ 2.2A)
- LT8309/LT3748 Demo Circuit - 60W, 12V Output, Isolated Telecom Supply (36-72V to 12V @ 5A)
- LT8309/LT3748 Demo Circuit - 40W, 5V Isolated Telecom Supply (36-72V to 5V @ 8A)
- LT3748 - Switching Regulators, LT8309 - Switching Regulators
Models for the following parts are available in LTspice:
- LT8309
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.
Evaluation Kits
LT8309ES5/LT3748EMS Isolated Demo Board | 36V ≤ VIN ≤ 72V; VOUT = 12V @ 5A
Resources
Reference Designs
20 W High-Efficiency Optocoupler-Free Flyback PSU for Solar Inverter Applications