Hello everyone and thank you very much for your answers!
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@raja.cedt
I'm trying to design a Pierce oscillator, however in all the schematic I found, the schematic wasn't transistor level.
I didn't use a regular inverter because I couldn't control the output voltage levels.
I have several constraints about my input voltage level and ouput voltage level. I must use 5V supply voltage on transistors that can hold only 3.3V and my output level must be 1.2V. (However you couldn't know that, I forgot to mention it, I'm sorry).
About the Barkhausen criteria, actually my testbench was wrong so I thought that I didn't match the Barkhausen criteria, but now with proper simulation configuration I'm following the criteria.
I've been on this design for a month now. From all the publications and books I read, the amplifier inverter was always shifting the phase by 180° (therefore the inverter amplifier was in its bandwidth). I was so doubtful about my work that I started to question everything in my design. My superior told me that the design oscillator should take something like 2 weeks, and I'm stuck on it for 1 month already so I was quite panicked.
Yes the Pnoise is my next step, I mean... as soon as my oscillator works fine and I know why.
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@smlogan, thank you for helping me again
http://web.mit.edu/klund/www/weblatex/node4.htmlokay, my world if falling apart... Well I prefer negative resistance anyway.
Quote:Second, in a negative resistance simulation, the fact that the magnitude of the negative resistance (and assuming the real impedance is negative in sign) exceeds the series resistance of the quartz crystal unit indicates that the transconductance exceeds the minimum required value for positive gain.
Thank you very much I tried to find the meaning of the negative resistance for a while, thanks to you I finally have it.
I'll try to get these texts and tutorials, so I can fully understand what I'm doing.
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@wave
Yes you are right, I removed the follower stage (as I didn't need to adapt the impedance anyway). I couldn't use an inverter amplifier because I have to control the output voltage levels.
I had to use the numerous bias, because of another issue. I'm using 5V supply voltage on 3.3V transistors, I have to "lower" the voltage on some transistors so they won't be overstressed (but I haven't taken care of this problem yet).
And I'm sorry I forgot to draw the parallel resistance but it's present.
My new schematic :
http://www.pdfhost.net/index.php?Action=Download&File=14f34384d8c3b7aac18e8950f4...--------------------------------------------------------------------------
Thank you all again for your help. My simulations are now working, I'm oscillating, PSS does converge (but I will have to increase the accuracy).
However I have another problem. The drive level of the crystal model is only 100uW and I'm consuming up to 1069uW. I saw in a publication that to solve this, you need to add a resistor between the amplifier output and the crystal input.
Will this addition change all my previous calculations?
Thank you again.