YUJIN
Newbie level 2
Hi
I want to design crystal oscillator (pierce) but i have in trouble...
Proposed oscillation frequency is around 39MHz
And i used crystal
L~4mH C~4.1fF R~10ohm Co~2pF
C1 C2=20pF(shunt cap for drain to gnd& gate to gnd)
Feedback resistor ~ 1Mohm
Vdd~1.5V
Transistor gm~80u
However, my oscillator input/output settles
to same voltage , not oscillate...
When i change crystal cap to 200fF by myself for just trying.. then it oscillates.
What is the problem? ..
Can crystal motional cap affect oscillation?
I want to design crystal oscillator (pierce) but i have in trouble...
Proposed oscillation frequency is around 39MHz
And i used crystal
L~4mH C~4.1fF R~10ohm Co~2pF
C1 C2=20pF(shunt cap for drain to gnd& gate to gnd)
Feedback resistor ~ 1Mohm
Vdd~1.5V
Transistor gm~80u
However, my oscillator input/output settles
to same voltage , not oscillate...
When i change crystal cap to 200fF by myself for just trying.. then it oscillates.
What is the problem? ..
Can crystal motional cap affect oscillation?