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Design >> RF Design >> Pseudodifferential Signaling
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Message started by DDC on Jul 3^rd, 2012, 12:07am

Title: Pseudodifferential Signaling
Post by DDC on Jul 3^rd, 2012, 12:07am

Hello,

I have the problem that the maximum supply voltage I can use is too small for the design of a gilbert cell. I decided to bias the transconductance stage of the gilbert mixer without a current mirror at the button. So I need to bias the BJT transistors like current mirros itself. Can somebody explain, what is the drawback of this ? I heard that when doing so you won't have AC common mode voltage rejection. Is that right and why ? Thanks for response.

Title: Re: Pseudodifferential Signaling
Post by raja.cedt on Jul 3^rd, 2012, 5:42am

how much vdd you have? if it is so low use modified Gilbert cell which has only 2 transistors in the stack from vdd to gnd.

thanks,
raj.