Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How does the crystal oscillator work?

Status
Not open for further replies.

qiuad

Newbie level 1
Joined
Oct 10, 2004
Messages
1
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
6
crystal osc, for help

I don't know how the osc is working, anyone can help me?
thanks.
 

Re: crystal osc, for help

Look!
 

Re: crystal osc, for help

M1 and M2 are the main differential amplifier. Its output is amplified by the second differential pair M3 and M4. Its output is taken from M4, through two Emitter followers M10 and M11 and fed back to the two differential inputs of the main differential amplifier M1 and M2.
If you follow the polarity of the feedback you will find that the feedback to M1 input is positive feedback, and the feedback to M2 input is negative feedback.
The crystal shorts to ground the negative feedback at M2 input only at its series resonance, so the net feedback left is positive, and if its magnitude is large enough, the circuit will oscillate.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top