who said , that the BJT can't be used as LNA ,
the noise figure of the BJT is much lower than the MOS , the gain of the BJT is much higher than the CMOS
the linearity is lower than the MOS , i think BJT matching is harder
Besides what has already been said, BJTs also have a lower 1/f noise. I don't think it is any harder to match a BJT vs. a MOSFET, from what I have experienced.
So, what is the common way to match a BJT to 50Ohms with a good NF?
krashkealoha said:
Besides what has already been said, BJTs also have a lower 1/f noise. I don't think it is any harder to match a BJT vs. a MOSFET, from what I have experienced.
if u are talking about integrated BJT , one common way is to use degenration inductor , to make the input impedance high , and also increase the Ropt , for minimum noise figure , the use sreise coil with gate , with this u can get good NF performance with BJT
if discreet , u can use microstrip matching network , also the discrete BJT's are optimized so that there input impedance is higher than integrated ones