Overview

The QS3251 is a high-speed CMOS TTL-compatible 8:1 multiplexer/demultiplexer that has 3-state outputs. The QS3251 is a function and pinout-compatible version of the 74F251, 74FCT251, and the 74ALS/AS/LS251 8:1 multiplexers. The low ON-resistance of the QS3251 allows inputs to be connected to outputs without adding propagation delay and without generating additional ground bounce noise. Mux/Demux devices provide an order of magnitude faster speed than equivalent logic devices. The QS3251 is characterized for operation at -40 °C to +85 °C.

QS3251 - Block Diagram
QS3251 - Block Diagram
  • Enhanced N-channel FET with no inherent diode to VCC
  • 5Ω bidirectional switches connect inputs to outputs
  • Zero propagation delay, zero ground bounce
  • Undershoot clamp diodes on all switch and control inputs
  • TTL-compatible control inputs
  • Available in 16-pin QSOP and S1 packages

Applications

  • Logic replacement
  • Video, audio, graphics switching, muxing
  • Hot-swapping, hot-docking
  • Voltage translation (5V to 3.3V)

Documentation

Design & Development

ECAD Models

Schematic symbols, PCB footprints, and 3D CAD models from SamacSys can be found by clicking on products in the Product Options table. If a symbol or model isn't available, it can be requested directly from the website.

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Diagram of ECAD Models

Product Options

    Processing table
    Pkg. Type
    Lead Count (#)
    Temp. Grade
    Pb (Lead) Free
    Carrier Type
    Moisture Sensitivity Level (MSL)
    Price (USD) | 1ku
    Buy / Sample
    Part Number
    QS3251QG8
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    		QSOP 16 C Yes Reel 1 0.4208
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