Serial to Parallel Converter with open drain outputs?

Discussion in 'The Projects Forum' started by Peace Frog, Apr 13, 2009.

  1. Peace Frog

    Thread Starter Member

    Apr 13, 2009
    First of all I apologize if this is in the wrong section as this is my first post.

    My next project is for a microcontroller class that's centered around the 8051. Having recently dug up a large cache of Nixie tubes I naturally have to build a clock.

    I did a little digging and came up with the HV5522 Serial to parallal converter with open drain outputs. This is exactly what I need but it's surface mount, and for the moment I'm limited to parts I can put on strip board. Anyway, I'm looking for a part with at least 10 open drain outputs that I can drive with TTL.

    I know I could do this with a shift register driving a bunch of FETs, but with a 6 digit clock and 10 control lines per digit I'm trying to cut down on individual parts. A few of my friends have made attempts at their own clocks, and I choked when I saw their 30+ transistors on each tube control module.

  2. RiJoRI

    Well-Known Member

    Aug 15, 2007
    Nuts & Volts magazine, October, 2006 had an article on making a Nixie tube clock. It may help for the hardware portion.

  3. Peace Frog

    Thread Starter Member

    Apr 13, 2009
    Thanks, I'll see if I can get access to back copies somewhere. Any other suggestions?
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    You're going to have lots of wires. Each Nixie takes 180 volts DC, and then 10 lines for the cathodes. Current is minute, but the voltage is a bit high for most IC's.
  5. Peace Frog

    Thread Starter Member

    Apr 13, 2009
    That's why I was particularly impressed with the HV5522.

    I'll be using a switch mode supply to get about 190VDC to drive the tubes. They are common anode tubes so the HV5522 just has to open the cathodes (which it is capable of doing even under the high voltage).