Overview
The LT8309IS5#TRMPBF, produced by Analog Devices Inc., is a secondary-side synchronous rectifier driver designed to replace the output rectifier diode in flyback topologies. This component enhances efficiency and reduces heat constraints associated with traditional diodes by utilizing an N-channel MOSFET. It operates in both discontinuous conduction mode (DCM) and critical conduction mode (CrCM), making it versatile for various high-efficiency flyback applications.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VCC Range | 4.5V to 40V | V |
| Maximum MOSFET Voltage | Up to 150V | V |
| Turn-Off Propagation Delay | 26ns | ns |
| Gate Driver Pull-Down Resistance | 0.8Ω | Ω |
| Quiescent Current | 400µA | µA |
| Package Type | 5-Lead Plastic TSOT-23 | |
| Operating Temperature Range | –40°C to 125°C (LT8309I), –40°C to 150°C (LT8309H) | °C |
Key Features
- Works with DCM and BCM/CrCM conduction modes
- Supports up to 150V MOSFETs
- Accurate minimum on and off timers for reliable operation
- Adjustable and accurate trip point: +5mV to –30mV
- Fast turn-off propagation delay of 26ns
- Low quiescent current of 400µA for high efficiency at low output currents
- Gate driver with 0.8Ω pull-down resistance for fast turn-offs
- Overtemperature protection
Applications
- High output current flybacks
- High efficiency flybacks
- Isolated telecom supplies
- Other applications requiring high efficiency and low heat generation in flyback topologies
Q & A
- What is the primary function of the LT8309IS5#TRMPBF?
The LT8309IS5#TRMPBF is a secondary-side synchronous rectifier driver that replaces the output rectifier diode in flyback topologies.
- What are the supported conduction modes for the LT8309?
The LT8309 supports both discontinuous conduction mode (DCM) and critical conduction mode (CrCM).
- What is the maximum MOSFET voltage supported by the LT8309?
The LT8309 supports up to 150V MOSFETs.
- What is the turn-off propagation delay of the LT8309?
The turn-off propagation delay of the LT8309 is 26ns.
- What is the quiescent current of the LT8309?
The quiescent current of the LT8309 is 400µA.
- What is the operating temperature range for the LT8309I and LT8309H versions?
The operating temperature range is –40°C to 125°C for the LT8309I and –40°C to 150°C for the LT8309H.
- What type of package does the LT8309 come in?
The LT8309 comes in a 5-Lead Plastic TSOT-23 package.
- Does the LT8309 have overtemperature protection?
- What are some typical applications of the LT8309?
Typical applications include high output current flybacks, high efficiency flybacks, and isolated telecom supplies.
- How does the LT8309 improve efficiency in flyback topologies?
The LT8309 improves efficiency by replacing the output rectifier diode with an N-channel MOSFET, reducing heat constraints and improving overall efficiency.
