I am looking to drive regular Nixies. I am trying to figure out how to read those datasheets! There are a lot of variations on a theme with this family of chips. I had to think for a bit, but I get what you are saying re. low voltage - I have to keep reminding myself that low voltage == ON (and I have to hit strike, not maintain) and high voltage == OFF! and that the current limiting resistor will drop the comparative voltage further.
I will go back and peruse the data sheets some more, though everyone seems to like the 5530. I looked at the HV5523, which also has 5V Vdd but a max of 220V output. However it also has a max low of 15V. I could use a current limiting resistor for this, but there is no specification of the min low, and I wonder if the comparative voltage could therefore vary between 220V and 205V? Just exploring possibilities at this point. On Tuesday, February 21, 2017 at 11:57:12 AM UTC-5, gregebert wrote: > > Are you driving segmented tubes (like the 7971) ? If so, I would advise > against the HV-series drivers because you will need several different > segment-currents. > > If it's a traditional 10-cathode nixie, where each numeral uses the same > current, the HV devices work great. There's a variety of opinions about > using drivers rated below the anode supply voltage. The legacy 74141, which > is rated around 45V, has been used for nixies for years and it's > suitability relies on the voltage-drop across a nixie. While it's probably > OK for bipolar (NPN) output drivers as long as the current is limited, it > *definitely* is *not* OK to exceed ratings for MOS devices because it > will cause destructive breakdown. > > I looked at the HV3418 datasheet, and I dont think it will suffice for > nixies because the spec value of the *low* output voltage at 5mA load is > 25V. If you are running from a +180V supply, the tube will 'see' less than > 155V because of the voltage-drop on the anode resistor. The ability to run > at +5V on the logic side may sound desirable, but the other specs in my > opinion make this device unsuitable. > > I cant say enough good things about the HV5530. I have a 14-tube clock w/ > IN-18's that has been running for over a year now with zero issues. I used > a level-shifter to drive the HV5530 inputs to 12V from my FPGA, which has > 3.3V I/O's. Instead of an anode resistor to set the segment current, I use > a PMOS device to generate constant current. > > > > > -- 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/e0d9cf6b-076c-4c53-ac9c-c5fc4bf6c3d2%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
