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High speed, high Hfe complementary transistors?

Discussion in 'Electronic Components' started by Tim Williams, Oct 18, 2005.

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  1. Tim Williams

    Tim Williams Guest

    I'm designing an IGBT gate drive. I need a complementary pair of high gain,
    high current transistors capable of switching in under 200ns (Zetex would be
    perfect, but all the datasheets I've looked at seem to be in the 600ns
    range).

    Or (since someone's probably going to post about it whether I like it or
    not) you could give a suggestion for a high/low side (half bridge) IGBT
    driver rated 600V.

    Through hole suggestions please.

    Tim
     
  2. Fred Bartoli

    Fred Bartoli Guest

    Use the ZTX618-619/718-720 from Zetex. They are absolutly perfect for this.
    The timing you're mentionning are not switching time: they include the
    storage time as well. More, these times are for saturated switching, which
    you won't have for a CC output stage and a capacitive load. You'll be in the
    few 10s of ns range.
     
  3. Tim Williams

    Tim Williams Guest

    "Fred Bartoli"
    Ok, but if the follower had to respond in the opposite direction in under
    0.5ns, wouldn't one transistor turn on significantly faster than the other
    turns off, causing shoot-through?

    (Yeah, it won't, but if there were say 40nH in series with a non-resistive
    gate capacitance, hmm that could never happen anyway with all the resistance
    present...)
    True, I'll be hard pressed to saturate a follower, especially for much of
    the entire cycle given a capacitive load.

    Thanks!

    Tim
     
  4. Fred Bartoli

    Fred Bartoli Guest

    0.5ns? And for IGBT drivers? Why not asking for ps?

    Do you understand that 0.5ns is 15cm light travel?

    Sorry to say that, but I guess you have to get down on earth and better
    understand all the details of how your bridge works, where the parasitics
    are, how to wire your system to deal whith them,... Then you'll get more
    realistic figures, much more than pulling them at random from your hat.
     
  5. Tim Williams

    Tim Williams Guest

    --
    Deep Fryer: a very philosophical monk.
    Website: http://webpages.charter.net/dawill/tmoranwms
    "Fred Bartoli"
    Oops, 0.5µs.
    (Unfortunately the rest of your post has no content to continue this
    conversation.)

    Tim
     
  6. Fred Bartoli

    Fred Bartoli Guest

  7. Jim Adney

    Jim Adney Guest

    No, I think it's really much closer to 0.5 nSec.

    c is approx 1 ft/nSec. 15 cm is approx 1/2 ft.

    That's in vacuum, though, so it will be slower in wires, but only by
    25-35%.

    -
     
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