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Murphy's friend

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Joined: 04/10/2019
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Posted: 09:03am 05 Oct 2023

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I'm finding it difficult to source suitable thru hole transistors for the totem pole driver, which will fit my PCB hole spacing.

Would these : BD681 & BD682 work? They ate 4A darlington transistors.

Thanks

pd--
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Posted: 11:24am 05 Oct 2023

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Do you mean to replace the 2sc6017 & 2sa2169

Murphy's friend

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Posted: 01:25pm 05 Oct 2023

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Yes, one of them appears to be no longer stocked at Digikey.

Solar Mike
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Posted: 10:21pm 05 Oct 2023

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Murphy's friend said I'm finding it difficult to source suitable thru hole transistors for the totem pole driver, which will fit my PCB hole spacing.

Would these : BD681 & BD682 work? They ate 4A darlington transistors.

Thanks

Don't think so, darlington types have a high CE saturation voltage, so will not switch the mosfets very well.

looks like the originals are now obsolete, seems there are some on AliExpress, whether they are originals or clones maybe hard to verify.

There is probably something else around with a similar spec, however it will take a lot of time to look at all the specs and compare. You want approx 10 amps, 50 volts, low CE saturation voltage < 0.6v and switching times around 50 nSec.
Would be easier to just use a single TO220 size mosfet driver chip, hmm pcb re-design.

Edit Look at the MJE200G(NPN), MJE210G(PNP), seem fairly fast switching with low sat voltage.

Cheers
Mike
Edited 2023-10-06 08:36 by Solar Mike

Murphy's friend

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Posted: 01:44pm 06 Oct 2023

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Thanks Mike. RS has the MJE200(210)G, unfortunately in lots of 25 only.

I appreciate your input, I'm better at building projects rather than designing them, so picking the right part is not always easy.

tinyt
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Posted: 01:53pm 06 Oct 2023

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For what it is worth, the chinese inverter I am testing uses complementary pairs 2SD882/2SB772 driving 6 HY4008 mosfets.

nickskethisniks
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Posted: 09:05pm 06 Oct 2023

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Other options used in drivers:

TIP41 and TIP42
MJD44h11 and MJD45h11

Solar Mike
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Posted: 09:47pm 06 Oct 2023

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Looking at the data sheets for those suggested types, order of preference would be;

MJE200G(NPN), MJE210G(PNP)
2SD882/2SB772
MJD44h11 and MJD45h11

TIP41 and TIP42 -Don't use these, very slow and high CE sat voltage

Cheers
Mike

InPhase

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Joined: 15/12/2020
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Posted: 12:03am 07 Oct 2023

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The MJE3055T/MJE2955T combo work very well as FET buffer transistors and are readily available in single quantities from my suppliers.

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