BJT recommendation?

[Walter Harley]

I'm looking for a complementary pair of BJTs with characteristics similar to
PN2222A / PN2907A, but with a bit higher power. Audio frequency, hfe around
100 - 300, Vceo >= 20V; but they need to be able to dissipate 700mW
continuously (inside a small chassis), without damage. Case style is not
important, though I'd prefer TO220 or smaller - could do TO247 as a last
resort. I'd like to avoid heat sinks if possible because of the expense and
assembly time.

I'd have thought this would be easy to find, but I'm striking out. Only
candidates I'm aware of are some of the Zetex SOT223 packages, but those
seem to depend on large PCB copper area for their heat sinking.

If I could find a PN2222A/PN2907A die in a TO220, or maybe even TO5,
package, I'd be done - I just need junction-to-ambient that's 30% or so
better than what the plastic TO92 gives me.

Any advice welcome. (If I have to, I'll just pair up the TO92's, but I'd
prefer to avoid the extra board area, emitter resistor, etc.)

Thanks!

 

[Watson A.Name - \"Watt Su]

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:UN-dnVO829BQ99_fRVn-qQ@speakeasy.net...

I'm looking for a complementary pair of BJTs with characteristics
similar to
PN2222A / PN2907A, but with a bit higher power. Audio frequency, hfe
around
100 - 300, Vceo >= 20V; but they need to be able to dissipate 700mW
continuously (inside a small chassis), without damage. Case style is
not
important, though I'd prefer TO220 or smaller - could do TO247 as a
last
resort. I'd like to avoid heat sinks if possible because of the
expense and
assembly time.

I'd have thought this would be easy to find, but I'm striking out.
Only

Well, they're right under your nose. The 2N2219A and the 2N2905A are
the same chips as the 2N2222A and 2N2907A, but they're in a TO-5 can and
can dissipate something like 800mW. Sounds just right to me.

candidates I'm aware of are some of the Zetex SOT223 packages, but
those
seem to depend on large PCB copper area for their heat sinking.

If I could find a PN2222A/PN2907A die in a TO220, or maybe even TO5,
package, I'd be done - I just need junction-to-ambient that's 30% or
so
better than what the plastic TO92 gives me.

If you're willing to use Pro Electron Euro parts, the BD135 and BD136 or
other numbers in the same series will do the trick. They're TO-126, a
bit smaller than TO-220. With a clip-on heatsink, or screwed to the
board, they'll handle several watts. I got some of these from Futurlec
for 20 cents apiece. If you do consider the TO-5 transistors, you'll
have to pay more for the all metal case, probably double what the TO-126
cases cost. If you want anything more than a few hundred milliwatts,
forget about using a TO-92.

Any advice welcome. (If I have to, I'll just pair up the TO92's, but
I'd
prefer to avoid the extra board area, emitter resistor, etc.)

Yeah, I did that before. Worked for me. But I've never seen any
schematic anywhere that used that technique.

> Thanks!

 

[RST Engineering (jw)]

Our stock design uses the TIP29-TIP30 pair and we have had excellent
results.

Jim



"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:UN-dnVO829BQ99_fRVn-qQ@speakeasy.net...

I'm looking for a complementary pair of BJTs with characteristics similar
to PN2222A / PN2907A,

 

[Dave Platt]

In article <SrqdnX5zB8qhcd_fRVn-qw@speakeasy.net>,
Walter Harley <walterh@cafewalterNOSPAM.com> wrote:

If you're willing to use Pro Electron Euro parts, the BD135 and BD136 or
other numbers in the same series will do the trick.

Package looks perfect! It looks like min hfe is kind of low, but typical
hfe is decent; I might have to hand-screen, which would be a pain. Mouser
shows "non-stocked item"; Digikey doesn't list them.

Hmmm. It looks to me as if Fairchild has a bunch of variants of these
transistors, with part number suffixes which indicate the hfe binning.

Mouser has at least some versions (BD1361610STY, BD13616S and 16STU) in
stock. The ones they don't have in stock seem to be the "6" suffix,
which from the data sheet appears to be the lower-hfe versions.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Walter Harley]

"Dave Platt" <dplatt@radagast.org> wrote in message
news:1146kuosqkeh15e@corp.supernews.com...

Hmmm. It looks to me as if Fairchild has a bunch of variants of these
transistors, with part number suffixes which indicate the hfe binning.

Mouser has at least some versions (BD1361610STY, BD13616S and 16STU) in
stock. The ones they don't have in stock seem to be the "6" suffix,
which from the data sheet appears to be the lower-hfe versions.

Ah - I saw those and assumed they were different transistors that started
with the same couple of digits. Thanks! (You know what they say about
"assume"...) hfe-binned variants is exactly what I need.

 

[Walter Harley]

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:lrudnVte7t9lJt7fRVn-sw@speakeasy.net...

Ah - I saw those and assumed they were different transistors that started
with the same couple of digits.

On a closer look at the datasheet, light dawns. I thought the "hfe
classification" was telling me about statistical distribution (though the
numbers did seem peculiar). I realize now it's part number suffix. Duh.

 

[Watson A.Name - \"Watt Su]

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:SrqdnX5zB8qhcd_fRVn-qw@speakeasy.net...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:114535pd7eb7k50@corp.supernews.com...

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:UN-dnVO829BQ99_fRVn-qQ@speakeasy.net...
hfe around 100 - 300 [...] need to be able to dissipate 700mW
continuously (inside a small chassis), without damage.

Well, they're right under your nose. The 2N2219A and the 2N2905A
are
the same chips as the 2N2222A and 2N2907A, but they're in a TO-5 can
and
can dissipate something like 800mW. Sounds just right to me.

I'd be hesitant to pump 700mW through a device rated for only 800mW,
in a
closed airspace. Those ratings are based on 25C ambient right next to
the
device; in closed airspace, the air heats up, and you have to derate.
I'd
feel more comfortable with something rated at least 1W.


If you're willing to use Pro Electron Euro parts, the BD135 and
BD136 or
other numbers in the same series will do the trick.

Package looks perfect! It looks like min hfe is kind of low, but
typical
hfe is decent; I might have to hand-screen, which would be a pain.
Mouser
shows "non-stocked item"; Digikey doesn't list them. Nonetheless,
I'll do a
bit of hunting for them; they might do the trick. Thanks.

As I mentioned, but you apparently overlooked and snipped it, they are
available at www.futurlec.com for 20 cents in 1 unit quantity. They
come in three gain range classifiacations, -6, -10, and -16. So you
don't have to do any selection whatsoever. Mouser carries Fairchild,
and Fairchild makes them, so even if Mouser doesn't stock them you could
order them. Also there is Fairchild Direct, which may be cheaper than
Mouser.
http://www.fairchild-direct.com/esales/SearchProducts.jsp?partNumber=BD1
35

The 2N2219A and 2N2905A are rated for 3W at 25 degrees case, derate at
20mW/~C. So you can run them at 1W with a small finned heatsink. Aavid
makes some nice little heatsinks for TO-5s.

 

[Watson A.Name - \"Watt Su]

"RST Engineering (jw)" <jim@rstengineering.com> wrote in message
news:1145ul4f6vdmu96@corp.supernews.com...

Our stock design uses the TIP29-TIP30 pair and we have had excellent
results.

Jim

He complained that the BD135 and BD136 have too low gain, but the TIPs
have even lower gain than they do.

What he didn't see apparently was that the BDs have gain ranges, so he
can buy them with gains of 100 to 250, for example.

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:UN-dnVO829BQ99_fRVn-qQ@speakeasy.net...
I'm looking for a complementary pair of BJTs with characteristics
similar
to PN2222A / PN2907A,

 

[Walter Harley]

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:1147rln1b09aq27@corp.supernews.com...

As I mentioned, but you apparently overlooked and snipped it, they are
available at www.futurlec.com for 20 cents in 1 unit quantity.

I did overlook it - sorry.

The 2N2219A and 2N2905A are rated for 3W at 25 degrees case, derate at
20mW/~C.

But as I mentioned, "I'd like to avoid heat sinks if possible because of the
expense and assembly time." Maybe you overlooked that

Anyway, the BD135/BD136, with hfe binning and easy availability now that I
know how to look, are clearly the right answer, and I do appreciate the
help!

 

[Watson A.Name - \"Watt Su]

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:XamdnVMxkp1Ey9nfRVn-iA@speakeasy.net...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:1147rln1b09aq27@corp.supernews.com...
As I mentioned, but you apparently overlooked and snipped it, they
are
available at www.futurlec.com for 20 cents in 1 unit quantity.

I did overlook it - sorry.


The 2N2219A and 2N2905A are rated for 3W at 25 degrees case, derate
at
20mW/~C.

But as I mentioned, "I'd like to avoid heat sinks if possible because
of the
expense and assembly time." Maybe you overlooked that

Again,. I think you snipped the part where I said to use a HS or the PC
board.

Anyway, the BD135/BD136, with hfe binning and easy availability now
that I
know how to look, are clearly the right answer, and I do appreciate
the
help!

HTH.

 

[Walter Harley]

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:114535pd7eb7k50@corp.supernews.com...

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:UN-dnVO829BQ99_fRVn-qQ@speakeasy.net...
hfe around 100 - 300 [...] need to be able to dissipate 700mW
continuously (inside a small chassis), without damage.

Well, they're right under your nose. The 2N2219A and the 2N2905A are
the same chips as the 2N2222A and 2N2907A, but they're in a TO-5 can and
can dissipate something like 800mW. Sounds just right to me.

I'd be hesitant to pump 700mW through a device rated for only 800mW, in a
closed airspace. Those ratings are based on 25C ambient right next to the
device; in closed airspace, the air heats up, and you have to derate. I'd
feel more comfortable with something rated at least 1W.

If you're willing to use Pro Electron Euro parts, the BD135 and BD136 or
other numbers in the same series will do the trick.

Package looks perfect! It looks like min hfe is kind of low, but typical
hfe is decent; I might have to hand-screen, which would be a pain. Mouser
shows "non-stocked item"; Digikey doesn't list them. Nonetheless, I'll do a
bit of hunting for them; they might do the trick. Thanks.