> > On the production Nixie Ramos clocks I intend to use > these:http://www.nxp.com/documents/data_sheet/PMBTA42DS.pdfThey are dual > NPN 300v transistors that are really cheap. The downside is that there > are only 2 transistors per chip, so that's 5 per digit, so they are > going to significantly increase your part count on your board. But > they seem ultra-reliable, and at the cost I think they justify the > added part count. > > -Paul >
I had been looking at those PMBTA42DS dual NPN transistors for my nixie watch but found that the layout of the 2 transistors is not very convenient to cramp them onto a very small PCB. I prefer to have both collectors at one side of the chip and both bases at the other side. This is the case with the DMMT5551S. Only downside is that they are 180V models, so they are probably barely sufficient for your clock. I know there's been a lot going around that 50V would be enough etc etc, but if you really want the maximum performance of your clock/watch including PWM, blanking etc etc it is still better to go for high voltage drivers. I ended up using the BSS131 mosfets which are nearly impossible to cramp onto a tiny board, but they still fit and it also saved me a base resistor. Michel -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
