Hi There also are logic families that are 5V tolerant when run off of 3.3V. That makes finding a “translator” the same as finding any chip from that family. This may or may not make things easer to do / easier to find.
One of many families is the NC7SZ series. One common gate: https://www.onsemi.com/pdf/datasheet/nc7sz125-d.pdf <https://www.onsemi.com/pdf/datasheet/nc7sz125-d.pdf> Should be pretty easy to find. The gotcha with resistive dividers is the “lowpass” filter you create between the R of the divider and the C of the input. That can make the process a bit noisy / flakey. Bob > On Jan 28, 2022, at 3:20 PM, Andrew Kalman <aekal...@gmail.com> wrote: > > I find that the best way to handle these translations is to use one of > TI's level translators ... each chip has two power supply rails, and > translation is done transparently across the chip, and there is good max > voltage overprotection on both sides as well. I use them a lot to handle > 5V <-> 3.3V level issues. > > Try the SN74LVC8T245PWR for unidirectional level translating . They also > have some bidirectional ones ... > > --Andrew > > -------------------------------- > Andrew E. Kalman, Ph.D. > > > On Fri, Jan 28, 2022 at 11:41 AM folkert <folk...@vanheusden.com> wrote: > >> Hi, >> >> I bought a GPSDO. It outputs somewhere around 3V. This is connected to a >> picdiv and then to a raspberry pi. The picdiv is happy with 3.3v, the rpi >> as well. All good. >> >> Now I bought a "Square Wave Amplifier" by BG7TBL ( >> https://www.aliexpress.com/item/4000192799858.html?gatewayAdapt=glo2nld&spm=a2g0o.9042311.0.0.3d764c4dMZPAX8 >> ). Documentation I could find was a bit vague about the >> output voltage but I measured 5v with a scope (see >> https://vanheusden.com/permshare/scope.png - the scope software says >> 2MHz but output is really 10MHz). >> >> I did not study electronics, am only a electronics-hobbyist so bare with >> me when this is a dumb question. >> >> The RPI doesn't like 5v on its GPIO pins. >> So I wonder: >> - can I feed the picdiv 5v on its GPIO pin while giving it a 3.3v >> voltage so that it outputs 3.3v as well to the rpi pins? >> - or should I use a voltage divider? I was thinking of a 4.7k ohm and >> 8.2k ohm resistor giving slightly less than 3.2v - will that work? or >> will that attenuate the signal too much? The 50 ohm bnc cable between >> the amplifier and the rpi is 3m long. Anything else I should be aware >> of? >> >> >> Regards, >> >> Folkert van Heusden >> PD9FVH >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send >> an email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.