You can not replace both with the same transistor .
BC141 is NPN.......... near equivalent BD139
BC161 is PNP.......... near equivalent BD140
Electrically they look like near equivalents but of course the cases are totally different BCs....TO39 BDs....TO220
Also the BCs could have been bought as a matched pair ( dependent on circuit cofiguration ).
BC141 is NPN.......... near equivalent BD139
BC161 is PNP.......... near equivalent BD140
Electrically they look like near equivalents but of course the cases are totally different BCs....TO39 BDs....TO220
Also the BCs could have been bought as a matched pair ( dependent on circuit cofiguration ).
BC639/640 are the TO92 versions of the BD139/140
this is absolutely wrong .... 639 is a 0.5A device and 139 is 1.5A device ... how you come up with a thing like that ?
Sakis, he is right. The bc639 is a 1A, max 1.5A. Its the same chip put into a TO126 package for higher dissapation. I got this info many years back straight from philips when I wanted info regarding the datasheets. To get all relevant data one can cunsult bc639 datasheets. Some parameters deteriorate a little because of higher the parasitic capacitance in the TO126 but if you look closely the datasheets are identical except for the power ratings. Looking at the modern version of bc639 from onsemi it seems they kept the manufacturing way to get bd139.
well the first datasheet i run in to from alldatasheets was from MOT and says 0.5 A expected for a TO92 device
BC639 pdf, BC639 description, BC639 datasheets, BC639 view ::: ALLDATASHEET :::
BC639 pdf, BC639 description, BC639 datasheets, BC639 view ::: ALLDATASHEET :::
I dont think thats the case maybe with components manufactured in china as replacements. The ones by reputable manufacturers like onsemi, fairchild etc seem to be using the same setup.
Ill see if I can get answer to this from Onsemi or Fairchild, will be interesting.
All I know is that the Philips BC639 / BCX56 / BCP56 (/ BD139, discontinued) differ quite a bit from your average Fairchild or STMicro BD139.
Fairchild BD139s are modeled with Cje = 293p, Cjc = 49p, tf = 585p.
Philips BCP56-16s are modeled with Cje = 144p, Cjc = 21p, tf = 780p.
There's no way in hell these are even close to the same die.
The only BC639 model I could find (aside from an old Siemens BC637) was for a Zetex: Cje = 108p, Cjc = 16p, tf = 0.8n.
Fairchild BD139s are modeled with Cje = 293p, Cjc = 49p, tf = 585p.
Philips BCP56-16s are modeled with Cje = 144p, Cjc = 21p, tf = 780p.
There's no way in hell these are even close to the same die.
The only BC639 model I could find (aside from an old Siemens BC637) was for a Zetex: Cje = 108p, Cjc = 16p, tf = 0.8n.
I hope youre not relying on spice models for the figures, they are hopeless some times but in the case of the fairchild could be right, 49pf at 0 volt will equate to about 12 to 14pf at - 10v VCE. Thats what I reckon for the part. BC639 is around 6p 7p at -10 vce.
Zetex model seems correct too 16p at 0 gets you about 6pf -8pf at -10vce.
Theres one factor youre forgetting, when a different package is used for the transistor parasitic capacitances increase, this will influence other parameters like ft too.There exists 2 spice parameter for this in IC design but in the case of discretes these arent used for simplicity.
Zetex model seems correct too 16p at 0 gets you about 6pf -8pf at -10vce.
Theres one factor youre forgetting, when a different package is used for the transistor parasitic capacitances increase, this will influence other parameters like ft too.There exists 2 spice parameter for this in IC design but in the case of discretes these arent used for simplicity.
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