Texas Instruments CD4028BE

Thread Starter

Chris_1566064180

Joined Aug 17, 2019
4
Hello all,
I’m not an electronics expert or electrical engineer. I am an aircraft engineer with experience in avionics. For most of my career I’ve turned wrenches and solved problems with various aircraft. With that tidbit of information on to my question.

I am creating a Nixie tube clock. I’ve looked high and low for this answer with no firm understanding if I am correct in my assumption. I may have answered the question in my own way, but I wanted to be sure.

Can a Nixie tube be driven by the TI CD4028BE BCD? https://www.ti.com/store/ti/en/p/product/?p=CD4028BE

My thought is no. That it cannot handle the higher voltage, like the 74141 IC could. http://www.allspectrum.com/ic/english-datasheet-1.jpg

Thanks for the help to answer my question.
 

jbeng

Joined Sep 10, 2006
75
Page 4 of the cd4028b datasheet from TI shows that it can only drive Nixie tubes with an additional, external drive transistor for each numeral in the tube.

Nixie drive.jpg
 

MrChips

Joined Oct 2, 2009
22,068
The answer is no. CD4028BE cannot drive nixie tubes on their own.
You need external high voltage transistors to interface to nixie tubes.
 

Thread Starter

Chris_1566064180

Joined Aug 17, 2019
4
Thanks for the quick replies. I don't think adding 40 transistors to my PCB just to use the Texas Instrument chip is worth the real estate or time. I'll investigate the high voltage solution others have listed in their projects. I was hoping to avoid pad soldering that is required with those chips.
 

Thread Starter

Chris_1566064180

Joined Aug 17, 2019
4
Page 4 of the cd4028b datasheet from TI shows that it can only drive Nixie tubes with an additional, external drive transistor for each numeral in the tube.

View attachment 184120
@jbenq I just had a thought. Since I would only be driving one number at a time, is it possible to chain all the numerals for one tube through a single transistor? Instead of having 40 transistors have 4?
 

Bernard

Joined Aug 7, 2008
5,681
Have you considered the RCA Numitron or similar filament displays? Operate on 5 V or less. I used them in a digital clock & alarm monitoring console back in mid 1970's. Pictures on line.
 

Thread Starter

Chris_1566064180

Joined Aug 17, 2019
4
Have you considered the RCA Numitron or similar filament displays? Operate on 5 V or less. I used them in a digital clock & alarm monitoring console back in mid 1970's. Pictures on line.
I'll check that out Bernard. Thanks for the information.

I intend on using the nixies. I am sitting on 40 of them. :eek:
I'd like my first clock to look like something from out of Fallout 4. Colored Vault-Tec blue and yellow of course.

It appears you cannot edit previous posts after someone has posted, unless I am missing something. I wanted to edit post #6 as I see the error of my thought process once I drew it out on paper.
 
Last edited:

MrChips

Joined Oct 2, 2009
22,068
Modern clocks can be built with a minimum of components. You are attempting to build a retro-style clock. In this case, you just have to live with the fact that you will need 40 driver stages for 4 nixie tubes. That's life!
 

jbeng

Joined Sep 10, 2006
75
The only way to reduce the transistor count would be to multiplex the displays. Direct driving them with the 4028 will require 1 decoder/driver chip + 10 transistors per tube.

The datasheet for the 74141 says it is designed to do what you want with no external transistors. You'll need one for each tube. If you can get your hands on some of those, that's probably the route I would go.

Shortest distance between two points, as it were.

Here's a link I found on how to do it...
http://kevinrye.net/index_files/driving_a_nixie_with_a_74141_bcd_decoder.php
 
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