CD4504B is a TTL->CMOS or CMOS->CMOS level translator: http://www.onsemi.com/pub_link/Collateral/MC14504B-D.PDF that works well in similar circuits and will probably work just fine here too. Maybe the CD40109B can be used in the reverse direction if needed: http://www.ti.com/lit/ds/symlink/cd40109b.pdf. Otherwise a few transistors and discrete components will work just fine too.
/Martin On Tuesday, 21 April 2015 22:53:44 UTC+2, Mitch wrote: > > The attached data is for the LM339. It's called a comparator, but is it > the best choice? > > If I understand the formula correctly, if Vcc is +12v and Vin is +5v, a > good value for Vref is around 4v. Using the formula, if Rref is 100 ohms > than R1 should be 200 ohms. Five resistors are needed for each of the four > comparators, for a total of twenty resistors. > > All four of the clock kits I have that use Supertex chips just run them on > +5v, with no issues. Maybe this isn't worth the trouble. > > Mitch > > > > On Tuesday, April 21, 2015 at 4:27:53 PM UTC-4, jrehwin wrote: >> >> I had an unpleasant experience about 30 years ago (yeah, before the web >> existed and you had to use *printed* databooks...) with a comparator >> because I failed to read the datasheet correctly. I didn't realize it had >> an open-drain output, and I nearly went berserk trying to figure out why >> the bloody thing's output never went high. After adding a pullup resistor I >> got the output to go high, but it wasn't a nice sharp edge. >> >> >> Ah, the LM339! I made the exact same mistake, about 18 years back. I >> even wrote it up in my blog at the time: >> >> http://madbodger.livejournal.com/75916.html >> >> - John >> >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/1a668d69-56ed-4717-9450-794516955348%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
