I'm desigining a front end for WCDMA receiver and i have designed the LNA and working in the mixer..
But i need to bias the LNA (and of course the mixer later ) so what type of bias circuit i can use..
I read a little about the constant gm bias but this needs an external resstance which i think it is not that pretty solution..
so any help in any topic will be highly appreciated..
Best Regards,
Mostafa El Khouly
AA
i have worked with alot of chips from very big companies , in CDMA fornt ends , and i can say everyone have internal constant gm bias , and we add a very high quality resistor off chip , so the constant gm circuit work , so it is good solution
other wise u need to a good bandgap reference and bias cell for ur LNA and mixer 4 sure
thanks alot khouly, so it is normal speaking that i use a constant gm bias circuit and put a high quality off chip resistance ..
if i wanted to make this resistance on chip , will there be any practical case or it will be catastrphe