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500KHz peak detector
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ricko_uk:
Hi,
I have to make a peak detector of up to 500KHz. Using some of the classic configurations require a more expensive (high speed high slew rate op-amps).

I have come across a comparator-type peak detector below but it start introducing error at 100KHz

Any other suggestions for higher frequencies up to 500KHz? Or at the absolute minimum 250KHz?

Many thanks :)

 
graybeard:
what is the range of signal amplitudes?

do you need both positive and negative peaks?

what are the source and load impedances?

you need to define your requirements more completely
vk6zgo:
An old style "peak & hold" detector can work up into UHF, but may have limitations, in that very fast peaks in the midst of a lower frequency signal may be missed.

If you need to detect rarely occurring transients, you are pretty much stuck with doing it digitally, & will need a very high sample rate, plus a lot of memory.

If the transients you want to see are very infrequent, maybe the device could check what it has "seen" for a set previous time, flag that as "no transient found", empty & re-use the memory.
Circlotron:
Precision AM detector?
I have a circuit at home I'll post later.
ricko_uk:
Thank you Circlotron and Greybeard,

Circlotron, look forward to it. Thank you! :)

Greybeard,
- signal amplitues as mentioned from few tens of mV to 4.5V. It depends on the configuration for every specific application. Most cases are between 1.5 and 4.5V.
- the signal is as just a fixed sinewave
- detection of both positive and negative but no need to differentiate (i.e. a full wave rectifier would solve that)
- source and output impedances are buffered with op-amps so generally speaking at this stage no major issues there that I can think of

Thank you both :)
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