Quad Bus-Switch Mixer

I developed a mixer topology that’s based on the familiar quad diode balanced mixer, but using FST3257 SPDT CMOS bus switches instead of diodes. Initial results are very encouraging, with conversion loss under 4.5db and IP3 at least +30 dbm. Transformers are 4 turns #34 trifalar twisted wire on BN43-2402 cores. I’ll write more about this later…

. Stay tuned.

FST3257 mixer

Breadboard

FST3157 Mixer

Bus Switch Mixer Schematic

..

 

FST3257 mixer conversion loss 2dB per div

Conversion Loss @2db/div

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2 Responses to “Quad Bus-Switch Mixer”

  1. darren heywood January 23, 2018 at 3:09 pm #

    I breadboarded your mixer, works very well with excellent strong signal cruncher, however conversion loss is found to be -8dBm.cheers darren-2W0EPI

    • w3jdr January 29, 2018 at 8:29 am #

      Darren
      Check that the transformer are wound exactly as specified and that bias voltage is 2.5V I’ve built several of these and the conversion loss at HF is always around 4.5 dB.

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