Hi Just about any of the modern ‘125 or ‘126 buffer gates will do a pretty good job of generating a logic output:
https://www.fairchildsemi.com/datasheets/NC/NC7SZ125.pdf https://www.fairchildsemi.com/datasheets/NC/NC7SZ126.pdf http://www.nxp.com/products/discretes-and-logic/logic/quad-buffer-3-state:74ABT125 http://www.nxp.com/products/discretes-and-logic/logic/quad-buffer-3-state:74ABT126 http://www.ti.com/lit/ds/symlink/sn74lvc126a.pdf http://www.ti.com/lit/ds/symlink/sn74lvc126a.pdf The typical ’04 inverters also will do the job: http://cache.nxp.com/documents/data_sheet/74AHC_AHCT1G04_Q100.pdf?pspll=1 http://www.ti.com/product/sn74ahc1g04 http://www.ti.com/product/sn74ahc1g125 The list could go on for several pages…. 3.3V into 50 ohms is 66 ma. Close to the rail most gates will only put out around 10 ma. If you want to drive close to the 3.3V level, you will need to parallel up about 6 to 8 gates. It’s probably best to drive them all from a single high speed gate output. If you are picky about the levels, twice that number of gates may be needed. Since you are driving out of an “un-terminated source”, you can expect a bit of ring on your cable. If you want to deliver 3.3V into a 50 ohm load out of a 50 ohm source, you will need a circuit that will handle a 6.6V supply. You *might* be able to select gates that won’t blow up at that voltage. The current will be 2X higher so you will need a few gates. In this case, each one gets a series resistor in it’s output to make up the 50 ohm total. Bob > On Apr 16, 2016, at 2:29 AM, Anders Wallin <anders.e.e.wal...@gmail.com> > wrote: > > hi all, I wrote down some notes on a recent PICDIV build and measurements: > http://www.anderswallin.net/2016/04/picdiv-frequency-divider/ > > If/when I make v2 of this board: > - any suggestions for boosting the output amplitude of both 1PPS and 10MHz > CMOS? Something that drives 3.3Vpp into 50R with ~few ns rise time? > - any obvious mistakes that cause the phase-noise observed? Mostly I think > 50/100Hz and harmonics would be nice to suppress.. > > thanks! > Anders > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
