[time-nuts] 74HC4046 receiver
Pete
peterawson at earthlink.net
Thu Apr 9 01:09:24 UTC 2009
Bruce,
Quite correct, fumble fingers win again. As they say "here's
the rest of the story".
I was able to measure just 1 part. It is a NSC MM74HC4046N,
date code 9018, presumably still available from Fairchild. The VCO
was disabled (INH=H), the COMP input was grounded & I looked
at the PC1 output. Transition times were <3ns & abberations were
<5%. The resulting jitter measures:
Input Vp-p Jitter ps rms
2.36 8.6
2 8.8
1.5 9.2
1 9.5
0.7 10.2
0.5 11.1
0.3 14.5
I tried comparing this with a 74AC04, but my setup must be too
noisy as the best the 'AC04 could do was 12ps rms. The input to
the 'AC04 was AC coupled & yielded 49/51% duty cycle, apparently
switching cleanly with the 2.36Vp-p input. Ground bounch & ringing
were <10%.
Pete Rawson
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