"DanielK" <kuriloff@...> wrote:
Can anyone tell me if the CD4511 can drive B7971 Nixie tubes
directly or must I have each tube segment driven in addition
with mpsa 42 HV transistors?
I basically want to use the CD4511 in place of the DS8880 HV
BCD-to-7 Segment decoder ...
Dan
No, a CD4511 can't drive a nixie (B7971 or any other) directly. You need to add those HV xstrs (MPSA42), with 42 base resistors (22K ea). You can substitute some old fashion SN75468 relay/lamp drivers, for the HV transistors. One SN75468 will replace 7 MPSA42 xstrs, and 7 22K resistors. However, you may need to add a mid-pull circuit. Use an resistor divider to make a voltage around 80V. Tie that to the pin on the SN75468, that's common to all its protection diodes (pin 9). This will keep the cathode from exceeding the 100V rating of the SN75468.
