Im simulating a pierce crystal oscillator on synopsys software. The design that i've made is to achieve 10MHz frequency. The problem is the circuit that ive made doesnt oscillate. Initial condition also been included before the inverter. Is there any error that I've made in this circuit? Thank you


RF = 1M Ohm
R1 = 1k Ohm
C0 = 6p F
Cstray = 5p F
C1 = C2 = 22p F
Pmos W/L = 6u/1u
Nmos W/L = 3u/1u

 

Have you ever had an oscillator work in your simulator before? I ask, because an oscillator is fairly difficult to get to start in a simulator. What I do, is place a CLOSING SWITCH that closes at T=0.1 seconds in the base of the active element. Sometimes it works, sometimes it doesn't. Sometimes, changing the switch close time helps.

Also, your circuit isn't easily readable.

 

When you asked for help, but you attached a unreadable value, I'm not sure how our helper how to help you?

Please reattach a clear circuit.

 

Sorry about that.. I will attach it back later, since the file is at another pc that has synopsys..

 

Have you ever had an oscillator work in your simulator before? I ask, because an oscillator is fairly difficult to get to start in a simulator. What I do, is place a CLOSING SWITCH that closes at T=0.1 seconds in the base of the active element. Sometimes it works, sometimes it doesn't. Sometimes, changing the switch close time helps.

Also, your circuit isn't easily readable.

Im working with ring oscillator and also VCO circuit. And it works pretty well, only the pierce crystal oscillator doesnt oscillate

 

When you asked for help, but you attached a unreadable value, I'm not sure how our helper how to help you?

Please reattach a clear circuit.

Sir, here is the reattach part. Sorry i have to seperate it since the component symbol is small.

 

Hi

Where are you setting initial conditions? I don't see the setting(s) anywhere.
Try setting one side of the inverter (try output side) to 0 volts.

 

Hi

Where are you setting initial conditions? I don't see the setting(s) anywhere.
Try setting one side of the inverter (try output side) to 0 volts.

Hello there.

I already set the initial condition at the input side (to 0 volt).
By the way is there any difference if i set the initial condition at the output side?

 

I would follow the rise of the power supply voltage.
Which side of the inverter reaches steady state first based on power up?
Are you able to set the ramp up time of all power sources?
Try setting the power supply voltage source rise time to 25uS.
Are you using the .UIC directive?

I mainly use LTspice and this is usually solved by ramping the power supply or
setting the initial conditions of specific nodes or devices (like caps).