Hi,
During my project in uni I have come across some things I am having difficulty understanding.
I have to design an amplifier to work up to atleast 2MHz, with a voltage gain of atleast 100.
I started my design with a common emitter amplifier using a BC107 BJT transistor. Unfortunately it only operated at 200Khz with gain of about 30dB.
I have now designed a cascode amplifier and Im having difficulty calculating the bypass capacitors.
My DC design is for 2SC2166:
Vcc = 10V
Ic = 5mA
gm = 70
RL = (10-7.5)/5mA = 500
Re = 1/5mA = 200R
R3 = (1+0.7)/714uA = 2380R
R2 = (7,5-5)+0.7/786uA = 4071R
R1 = (10-3.2)/865uA = 7861R
The rules I have used are:
Vre = 10% Vcc
Ir1 = 10 X Ib
I would really appreciate if someone could explain how the capacitors are calculated, I understand that I might have to make a small signal model, but still having difficulty with it.
During my project in uni I have come across some things I am having difficulty understanding.
I have to design an amplifier to work up to atleast 2MHz, with a voltage gain of atleast 100.
I started my design with a common emitter amplifier using a BC107 BJT transistor. Unfortunately it only operated at 200Khz with gain of about 30dB.
I have now designed a cascode amplifier and Im having difficulty calculating the bypass capacitors.
My DC design is for 2SC2166:
Vcc = 10V
Ic = 5mA
gm = 70
RL = (10-7.5)/5mA = 500
Re = 1/5mA = 200R
R3 = (1+0.7)/714uA = 2380R
R2 = (7,5-5)+0.7/786uA = 4071R
R1 = (10-3.2)/865uA = 7861R
The rules I have used are:
Vre = 10% Vcc
Ir1 = 10 X Ib
I would really appreciate if someone could explain how the capacitors are calculated, I understand that I might have to make a small signal model, but still having difficulty with it.