Paul Burridge wrote:
Hi chaps,

Heading sums it up. I'm using a 74HC04 to 'square-off' a sine wave,
but it's causing a fair amount of ringing on the output signal's highs
and lows which appears to be finding its way through to the eventual
final stage. How do I best eliminate (or at least drastically reduce)
this nuisance? The square wave frequency is 8Mhz., btw.

Thanks,

p.

If you put a low inductance termination resistance right at the pin with
no wire and a low inductance bypass cap at the power supply and properly
introduce the signal to a scope, is the ringing still there? If it
ain't, the chip ain't causing it. Does the output ring with a square
wave input? Ringing is often more about the
interconnect than the chip...often...not always...
Oscillation, which can look like ringing is often about the input drive
for low dv/dt inputs.
Observed ringing, as opposed to Actual ringing can also be all about
measurement technique.


Can you be more numerical about "fair amount"? Amplitude and frequency
of the ring? Getting rid depends on how much you got and how much you
can stand and what you're driving.
mike

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