HELP : How to set Gilbert MIxer input swing
People usually said large LO signal and Small RF signal.
Any one give a detail example, what's the swing value of LO & RF signal.?
Thank you very much
It is very hard to say. It depends on process and supply voltage. Typically there is a sweat spot for LO that maximize linearity, noise and gain for gilbert cell mixer. In my case, i use 0.5Vp for my LO
the large lo signal is for the passive one.for gilbert typically we use 5dbm for lo but sometimes 3dbm will be enough alo.it depends on your circuit conditions and your requirements for your mixer parameters.and your rf signal depends on your system linearity. usually the signal swing of rf is 10dbm lower than your ip3.
To drive hard the mixer, VLOpeak must be greater than 3x25mV=75mV..
In this case Differential amplifier will enter into saturation so that it will just operate as a switch...
Practical values are 200mVpeak...1Vpeak