HV logic switch using PDP driver that seems to obsolete

Discussion in 'General Electronics Chat' started by tbandtg, Aug 7, 2012.

  1. tbandtg

    Thread Starter New Member

    Aug 7, 2012
    I am trying to turn some 5v serial into what is basically 100v parallel logic, and am having a really hard time of it.

    What I want is to be able to serially control a parrallel 100v switch. In the on position it doesn't need to supply any more than a ma of current. But in the off it needs to sink 30 ma on 12 outputs and 15 ma on 14 outputs. with a minimum of 26 outputs.

    I need to do this on a 3 cm x 2 cm board.

    I originally was going to use a NEC UPD16305 because it totally fit the bill. It has a low N channel resistance so even at my high temp of 85 degrees if I doubled up on outputs for the higher current ones it would work. But this chip is a ghost it is so far out of production our people can only find it really expensive and really small quantities.

    Then I was looking at Supertex HV7224 now this chip is available and manufactured but has an n channel resistance over 6 times the NEC part. So it is no good.

    Do any of you know of a better way to handle this. Or of a PDP driver that is relatively small that handles 100v has a low N channel resistance. I talked to an fae at supertech and he suggested I use 26 switches and a driver but there is no way that will fit on a 3x5 cm board with a micro.