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NEX81812DA

NEX81812DA Production

Adaptive Synchronous Rectifier (SR) Controller

The NEX81811DA and NEX81812DA (NEX81811/2DA) are high performance synchronous rectification controllers used in switching mode power supplies. It supports operation in Discontinuous Conduction Mode (DCM), Continuous Conduction Mode (CCM) and quasi-resonant flyback converters.

The NEX81811/2DA regulates the forward drop voltage of an external synchronous rectifier (SR) MOSFET in two stages. This allows the SR FET to turn off quickly when the VDS becomes positive.

The externally adjustable turn-on blanking time can effectively prevent the synchronous rectifier from being falsely turned off due to leakage inductance and parasitic parameter oscillation.

The adaptive turn-on detection circuit can prevent the SR from being mistakenly turned on when the VDS DCM oscillation crosses zero during some load conditions. The adaptive turn-on detection circuit also enhances SR conduction efficiency during light load conditions, thereby improving the average efficiency of the power supply across the entire load range.

The synchronous switch can be configured at high-side or low-side output without auxiliary windings or other power sources, because the NEX81811/2DA has a self-supply capability.

The NEX81811/2DA uses TSOT23-6 packaging with low thermal resistance. This can effectively reduce the junction temperature of the chip, making it suitable for high-density power supply design.
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Product details

Features and benefits

  • Supports DCM, CCM, QR operation

  • Supports up to 800 kHz switching frequency

  • Standard and logic level MOSFET driving capability

  • Wide output range down to 0 V with 2-channel VCC supply

  • No need for auxiliary winding for high-side or low-side rectification

  • Smart proportional gate driver for fast SR turn-off at CCM

  • Adjustable turn-on blanking time for increased noise immunity

  • Proprietary adaptive turn-on detection prevents SR FET from falsely turning on during DCM operation

  • 10 ns typical turn-off propagation delay

  • Available in a TSOT23-6 FC package

  • ESD protection:

    • HBM: ANSI/ESDA/JEDEC JS-001 class 2 exceeds 2000 V

    • CDM: ANSI/ESDA/JEDEC JS-002 class C2a exceeds 500 V

Applications

  • USB PD/QC chargers

  • AC/DC adapters for portable devices

  • Flyback SMPS with high-efficiency requirements

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More information

Quality and reliability disclaimer

Support

Please contact us if you have any questions. If you are in need of design support, please fill in the technical support form, we will get back to you shortly.

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Longevity

The Nexperia Longevity Program is aimed to provide our customers information from time to time about the expected time that our products can be ordered. The NLP is reviewed and updated regularly by our Executive Management Team. View our longevity program here.

Sample

As a Nexperia customer you can order samples via our sales organization.

If you do not have a direct account with Nexperia our network of global and regional distributors is available and equipped to support you with Nexperia samples. Check out the list of official distributors.

Interactive datasheet

How does it work?

The interactive datasheets are based on the Nexperia MOSFET precision electrothermal models. With our interactive datasheets you can simply specify your own conditions interactively. Start by changing the values of the conditions. You can do this by using the sliders in the condition fields. By dragging the sliders you will see how the MOSFET will perform at the new conditions set.

Interactive datasheet