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.

Register Log in

Urgent help need in crystal oscillator design

Status
Not open for further replies.
goldsmith

goldsmith

Advanced Member level 6
Joined
Dec 14, 2010
Messages
3,981
Helped
741
Reputation
1,486
Reaction score
726
Trophy points
1,413
Location
Tehran - IRAN
Activity points
24,546
Hello Dudes
I have a 12MHZ crystal , and i have to design an oscillator with that , with 20V p-p (10v peak ).
( 12MHZ sine out put. with BJT . )
I don't know that what should i do , and i confused.
Guide me , please.
Thanks for your help
Goldsmith
 

In my view you should first make a opamp 12 MHz oscillator design ....then feed the output of opamp oscillator to an amplifer of BJT or FET....

Refer -

**broken link removed**

Op-amp oscillators simplify RF designs

Good Luck
 
Dear milind.a.kulkarni
Hi
Thanks for your helpful reply. but i need 20 v p-p in that frequency .and about oscillator with op amp , i think that when the op amp want to work as an square wave oscillator , it should can works at 7th harmonic (at least).
What do you think about that?
And what is your suggestion about 20V p-p oscillator?(12MHZ)
Best Regards
Goldsmith
 

I would preferably think of a single BJT oscillators for a sine crystal oscillator. Depending on the required output power and load isolation, a second buffer/amplifier stage can be added.

To achieve the intended output level with lower supply voltage, a circuit with output inductor is suggested.
 
Your Point is valid Goldsmith....I even agree with FvM too.....but my recommandation will be multistage amplifer circuit where you generate low voltage input oscillator and amplify it wil multistage .....even there too you will not get perfect sinusoidal output...it will be square wave but if you put the capacitor companesation ( means capacitor loads as the output stages of the amplifer) ....may get close to sinusoidal ....as capacitor will have expoential charging and dischanging and will be get super imposed on the Square or tapazodal output wave.....

Good Luck
 
Dear FvM and milind.a.kulkarni
Hi
Thanks for your reply . but is it possible that you give me a suggestion circuit in that frequency and that amplitude (pretty stable) , please?
Best Regards
Goldsmith
 

you are doing at 12MHz deisgn right....I had made a design for 100Khz and 50Khz square wave using Crystal....I am attaching the PDF based on crystal connected to NAND gate IC and ripple counter ....But for 12Mhz you need to modify it with crystal and connection......this was giving me stable 100 and 50 Khz output.....

May be helpful to you....

Good Luck
 

Attachments

  • 50KHz circuit.pdf
    99 KB · Views: 95
Dear Friends!
Thanks for all of your helpful replies.
Best Regards
Goldsmith
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top