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

what's wrong with my 32.768K clock source?

Status
Not open for further replies.
L

liuzhili

Member level 3
Joined
Oct 3, 2002
Messages
65
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
397
I made a board as this schematic to get 32.768K clock source, but it couldn't generator 32.768K clock freq. I saw more than 60MegaHz at TP25, What's wrong? I don't know how to do to get 32.768KHz clock?
any suggestion? or any other fine schematic that could generate 32.768Khz?
thank you~~~
 

The load capacitance of the 32768kHz crystal is ≈15pF, so you can't have 2 x 1nF caps near it ..

Try the following values:
C124 10pF (or less)
C255 33pF
R188 100kΩ-330kΩ
R190 10MΩ or more ..
Also, I can't see any reason why you have C286 and C287 connected to the output of the U20B .. just remove them ..

Regards,
IanP
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top