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Design >> RF Design >> Feedthrough and DC offset problems in Current mode passive mixer
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Message started by chethan_RFIC on Apr 26^th, 2017, 7:45am

Title: Feedthrough and DC offset problems in Current mode passive mixer
Post by chethan_RFIC on Apr 26^th, 2017, 7:45am

hi,

I am trying to design a Current mode passive mixer with ideal LNA(Transconductor) smal signal model at input of mixer(MOS switch) and TIA( transimpedance amplifier) small signalmodel at mixer output. i simulated this circuit with cadence virtuoso. I got gain, noise figure, linearity verified for mixer.

But when i tried to simulate LO to RF feed through which is causing the DC offset some interesting questions are coming in mind. input to the mixer is current and output also current. but LO to RF feed through is voltage. when mixer mixing current what happens to feed through voltage. how to measure the feed through, and DC offset caused by this.

one thing i understood is we cannot use the same procedure which is used for finding feed through in voltage mode passive or active mixer.

If any one good in this concept. Please help me.

Thanks
chethan