Is there some standard way to get information about BJT (Bipolar Junction Transistor) rise and fall times (the high power ones) ? In essence a IGBT is a BJT being driven by a FET, so there should be some high-power, medium-speed BJT.

  • \$\begingroup\$ What is the question? \$\endgroup\$
    – pjc50
    Commented Sep 11, 2013 at 9:58
  • \$\begingroup\$ @pjc50 I added an question mark for being more easy for you to get the question :) \$\endgroup\$ Commented Sep 11, 2013 at 10:05
  • \$\begingroup\$ high-power BJTs are dinosaurs, and if they're not already discontinued, I would not rely on their continued existence. IGBTs and MOSFETs have essentially supplanted the entire power BJT market. \$\endgroup\$
    – Jason S
    Commented Sep 16, 2013 at 18:56
  • \$\begingroup\$ @JasonS first, what is high-power is relative in the context. In case of BJT >1A of continuous current is considered high power. I don't think this transistors are "dinosaurs", and as current controlled devices don't think they are supplanted. As the post says IGBT are in essence a MOSFET driving a BJT, and you know that MOSFETs are not yet good for >100V (high rdson), so in theory IGBTs (insulated gate bipolar transistor), are the BJTs in the market today. \$\endgroup\$ Commented Sep 17, 2013 at 13:25
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    \$\begingroup\$ That's the link posted by some user that removed it later. It have the models for small signal and large signals BJT ecee.colorado.edu/~bart/book/book/chapter5/ch5_6.htm \$\endgroup\$ Commented Sep 17, 2013 at 13:27

1 Answer 1


Sure. Not all manufacturers specify the data for all their BJTs, but there are good data sheets around, for instance the 2SA2090.

Page 2 lists the delay times for a specific base current (Ton, Tstg, Tf):

2SA2090 datasheet example: rise, storage and fall times

(Source rhom.com)

Page 3 has a detailed test circuit and shows how to interpret the waveforms obtained using the test circuit:

2SA2090 datasheet example: rise/fall time test rig

(Source: rhom.com)

  • \$\begingroup\$ Yes, but that's a small signal transistor (well 0.5A is not that small depending on the context). Small signal transistor have more information, but power BJTs does not have such information, just the output capacitance, that as I read, is what I should consider. \$\endgroup\$ Commented Sep 12, 2013 at 4:24

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