10 MHz linear amplifier using HCMOS ?

[walker1]

Way back, when I designed this input, I put in a standard transistor stage in order to boost the input 10MHz sine wave to something a 74HC14 could handle.

As it much later turned out, the input level was about 1.5Vpp, so I have had quite some difficulties in reducing the gain in the stage. The transistor output is DC coupled to the HC14, which might not have been the best of my ideas at the time

However, I have x-tra 74HC04 inverters available nearby. But how fast can one of theese digital CMOS implemmented linear amplifiers run?
All I need seems to be a gain around 2, giving me 3Vpp for the schmit-trigger.

10 MHz in ---- Cap --- Res ------ HC04 inv ----------- Boost out
| |
------- Res --------

 

[VEBill]

The applications seems to call for a device (any device) with a zero-crossing input.

 

[walker1]

Well, possibly. Or I could bias the HC14 input at, say, 1.8V and couble the boosted 10 MHz through another capacitor.

But my main issue was, if the booster could be made with an HC04 as specified. Meaning, make as few modifications to the existing circuit board as possible. (still prototyping !)

We may also be able to increase the 10 MHz signal level at the source, but I am just as well interested in the possibility for this little circuit. I have used it before with no trouble around 20 kHz, but 10 MHz ?
We are venturing into alternative applications here, which are not that well specified in the standard datasheet

 

[VisiGoth]

Without admitting to using this before, you might want to look at slapping a cap across the feedback resisor. Then you can think of your R as only setting your DC bias point, the HC input should be such a small amount of current that the offset voltage won't be a problem.

What you really don't know is the variation in the gain and phase vs freq so you can get an idea about gain marginand phase margin. So, the cap feeback puts you more in a narrow band solution, somewhat reducing your gain margin problems.

As an aside, I have only done this at 1 MHz, but it was a comm link, so it had some lower frequency stuff.

GOod luck.