BJT Gilbert Mixer

[Hetfield]

Hello everyone
What should be the bias points for the proper working BJT gilbert cell and what is the relation between the current on the circuit and the circuit specifications. of course i want higher linearity and low noise but what should be the current on the circuit. and i'm having a trouble with the biasing should the Vds of the transistors high or low?
thanks in advance

 

[RCinFLA]

A lot depends on what frequency range you want. There may be a trade off of gain vs noise figure.

Look at the ft (current gain vs freq) of devices. Pick a high enough current to get reasonably good current gain.

Make sure devices do not go into saturation. Keep at least a few tenths of a voltage collector voltage over base voltage. You have lower stage and upper switching stage.

Output collectors must have high enough voltage and enough room for AC output swing without going into saturation.

 

[BigBoss]

What Gilbert Cell you talk about ?? Long Tailed Circuit or ?

 

[vfone]

...What should be the bias points for the proper working BJT gilbert cell...
...i'm having a trouble with the biasing should the Vds of the transistors...

A BJT (Bipolar Junction Transistor) doesn't have Vds (drain to source voltage)