Searching for an ADC

Why must it have an internal clock? Serial or parallel output? What's the application?

The ADC product selection part of any major ADC manufacturers website will give you plenty of choice. e.g

Dave :)

Thanks for your reply, My application is a computer being used as a CRO. So my basic setup goes like this. I build a sample circuit whose output ranges from 100Hz to 1Mhz. This output is to be obtained on the CRO. So the output signals are converted into digital using ADC. This output is passed to the computer via parallel port using ATmega8 microcontroller.The microcontroller has an ADC but of very low sampler per second. For this purpose I need an ADC with 8 bit resolution parallel output, atleast

Run a google search on something called "crystal oscillator logic output"

Once you figured out the usual manufacturers and suppliers, the search in their datasheets will become a bit simpler.

Rene