[time-nuts] Squaring Tbolt 10Mhz output

[Hal Murray]

> I'm not sure everything can handle the 10Mhz signal.

Bingo.

LM339 (National data sheet)
  Response time: 	0.5 us

CD4049B/CD405B (from TI data sheet)
  Rise time is 80 ns
  Fall time is 30 ns
Those are typicals at 5 V with a 5V input signal.


The LM399 says "low power" which usually means low speed.

I occasionally go "oops" when I sanity check the speed on a circuit I'm about 
to build using HC/LS parts.  They aren't very fast, and the old 4000 logic is 
even slower.

10 MHz is about the corner for HC.  I use the HC163 (4 bit binary counter) as 
an example.  It has a max clock frequency of 25 MHz, so you think "no 
problems" at 10 MHz.  But the setup times are 30-40 ns and the clock-out are 
40-50 ns so doing anything interesting at 10 MHz gets tight.



-- 
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