Hi everyone. I know the title is little bit confusing but i really want to know if there's a difference. I ordered some MJW21193/94 from a reputed parts supplier & they send me two each of different package. I mean to-264 for PNP & to-247 for NPN. According to datasheet they have similar thermal properties but in the mjl21193 datasheet there is no mention of junction to ambient thermal resistant like mjw package. Physically MJL package is significantly bigger. sorry for this dumb question.
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I thought the same actually but the electrical characteristics are the same. So i think i should keep them without much concern because i'm not going to use those transistors for heavy duty PA amp.
They are close enough for practical purposes. Just don’t parallel the MJL with MJW or NJW because the latter will run a few degrees (or tens of degrees) hotter with high power. The difference being the *case to sink* thermal resistance which is higher for the smaller packages. This only responds to the average power dissipation not the peak, but if you average 50 watts the vbe’s might not track well enough for paralleling. Use on opposite sides of a complementary pair is no problem. The slopes of the Ib/Vbe curves between NPN and PNP is different in the high current region anyway just due to device physics so thermally induced mismatch will be lost in the noise. Often I end up using a current production TO-3P to replace an older discontinued TO-264, or one of those weird two-hole packages they don’t make at all anymore.
If you were worried about super accurate, cycle by cycle thermal tracking you’d be using the ThermalTrak devices anyway (if you can still even get them).
If you were worried about super accurate, cycle by cycle thermal tracking you’d be using the ThermalTrak devices anyway (if you can still even get them).
I think - but can't find the documentation - that these devices might have been shipped in TO-264 originally, but recently, and as part of OnSemi shifting production around the world, the TO-247 package is preferred. So I suspect your TO-264 devices are older stock, but I can't be certain.
As wg_ski mentions, the difference in thermal resistances between the packages means that you should not mix the two on a single polarity. It will mean though that an amp build may look a little odd with different size cases on the NPN and PNP output sides.
I'm sure if you contact ONsemi directly they will advise accordingly. You can give them the date codes too.
Are the PNP's older?
I'm not sure where you got those datasheet images from. The datasheets I have include a package drawing on the front page (and dimensions at the back). You seem to only have the left hand side of the page.
As wg_ski mentions, the difference in thermal resistances between the packages means that you should not mix the two on a single polarity. It will mean though that an amp build may look a little odd with different size cases on the NPN and PNP output sides.
I'm sure if you contact ONsemi directly they will advise accordingly. You can give them the date codes too.
Are the PNP's older?
I'm not sure where you got those datasheet images from. The datasheets I have include a package drawing on the front page (and dimensions at the back). You seem to only have the left hand side of the page.
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They still offer all multiple packages for most of the device types. I think the 4281/4302 are only TO-264, and 0281/0302 has *no* TO-264, but 2119x and 3281/1302 have all three. Fairchild 5200/1943 have no TO-247 but have the other two. I’m sure the TO-264 is on the chopping block within the next few years, and MJL will go the way of the MJH. The smaller packages are preferred by most volume users and that drives sales. They *may* keep a TO-264 around a while for some of their non-audio 400Vceo/1100Vcbo switching types because the newer TO-264 version with the notches around the leads can get to higher voltages. But even those types may go away as IGBTs take over those applications completely.
My guess is audio types will all go to TO-3P (N case) exclusively, and high voltage switching types gravitate toward TO-247 only (because of no exposed metal on the top side which can be sitting at 390 volts).
In the OP’s case, they may have shipped the alternate case because the one that was ordered was *out of stock* with a ridiculous lead time. A place like Mouser wouldn’t have done that - but back in the old days of mail order houses before the internet they would have if several package options were available. I ordered some surplus TIP35/36’s from BG Micro when they were still operating and half of them were TO-247 and half TO-218. That wasn’t that long ago.
My guess is audio types will all go to TO-3P (N case) exclusively, and high voltage switching types gravitate toward TO-247 only (because of no exposed metal on the top side which can be sitting at 390 volts).
In the OP’s case, they may have shipped the alternate case because the one that was ordered was *out of stock* with a ridiculous lead time. A place like Mouser wouldn’t have done that - but back in the old days of mail order houses before the internet they would have if several package options were available. I ordered some surplus TIP35/36’s from BG Micro when they were still operating and half of them were TO-247 and half TO-218. That wasn’t that long ago.
I don't know.
Yes you're right, i did not post full size of the page.
Anyway i thank you all for clearing my confusion. Btw the seller sent me original transistors🙂 I think i should place a new order but this time opposite package type for NPN & PNP 😉
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Originally these things came in a TO-3 package, and you can still buy them... for about $8 each.
What I find a little surprising is that they still offer these in both TO-3P and TO-247 packages...
What I find a little surprising is that they still offer these in both TO-3P and TO-247 packages...
