[time-nuts] minimalist sine to square

[Bruce Griffiths]

That network was for a 10MHz input.

For 5MHz double the L and C values.

For 3.3V one could use a lower step up say from  50 to 400 ohms rather than from 50 to 800 ohms.

1uH and 150pF and change 1k6 resistors to 820R.

Swap the 5V supply for a 3.3V supply.

L and C values aren't critical 5% or somewhat looser tolerance should be suffice.

Bruce

> 
>     On 20 January 2018 at 14:14 Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote:
> 
>     Something like the attached circuit is suitable for driving the MCU clock input directly.
>     The diodes should be schottky signal diodes like the 1N5711 series. The series resistors limit the diode peak current and the CLK input protection network current. It should work with inputs from 1V pp to 8Vpp. If SMT components were used it should all fit on a DIP compatible daughter board.
> 
>     Bruce
> 
>         > > 
> >         On 20 January 2018 at 12:37 Bob kb8tq <kb8tq at n1k.org> wrote:
> > 
> >         Bob
> > 
> >         With a 1V p-p sort of output, a simple matching network will get you into the 4 to 6V p-p range.
> >         Drive that into a 5V compatible CMOS gate and move on …. If you have a super hot output, put
> >         a 3 db pad on it.
> > 
> >         Bob
> > 
> >             > > > 
> > >             On Jan 19, 2018, at 5:40 PM, Tom Van Baak <tvb at LeapSecond.com> wrote:
> > > 
> > >                 > > > > 
> > > >                 Tom
> > > >                 What's the input signal amplitude?
> > > >                 What's the desired output signal (eg 5V CMOS, 3.3V CMOS etc)?
> > > >                 Bruce
> > > > 
> > > >             > > > 
> > >             It's for a typical 5 or 10 MHz OCXO / Rb / Cs with sinewave output; say, 1 Vpp. The output should be 3.3 or 5 V depending on what the MCU needs. It doesn't have to have stunning performance: think breadboard, PIC, Arduino sort of stuff. I was looking for something in a PDIP-8 package; the same as all the picDIV or picPET chips I use. That's why older parts like µA9637 / DS9637 came to mind.
> > > 
> > >             /tvb
> > > 
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