Hi,
I am designing a circuit using the Intel LXT915 IC which requires a 20Mhz oscillator input on a single pin. I bought an IXQ0 20Mhz chip from C-MAC. The output from this device is not exactly the square wave I was expecting, it has overshoot and is messy. My question is, do I have to add extra circuitry to get a clean square wave clock? The LXT is not working, and I assume that the messy clock wave is causing the problem. Can anyone help?
Much appreciated,
DumbMonkey.

 

Hi,
I am designing a circuit using the Intel LXT915 IC which requires a 20Mhz oscillator input on a single pin. I bought an IXQ0 20Mhz chip from C-MAC. The output from this device is not exactly the square wave I was expecting, it has overshoot and is messy. My question is, do I have to add extra circuitry to get a clean square wave clock? The LXT is not working, and I assume that the messy clock wave is causing the problem. Can anyone help?
Much appreciated,
DumbMonkey.

Are you sure the overshoot wasn't coming from your scope probe?
Is your scope probe calibrated? Does your scope probe impedance match the
impedance of your scope?

Were you using a ground probe wire to make your ground connection?
You can't use a ground probe wire when making high frequency measurements.
You need to use coax jacks or rest your probe across test points.

For some pictures see ---
http://www.luciani.org/eng-notes/ee-notes/ee-notes-index.html

(* jcl *)