On 15/08/2018 01:27, pcdhobbs@gmail.com wrote:> Both also obsolete. :(I object to that terminology. If a manufacturer is not capable of making, or unwilling to make, or too inept to sell, something as good as they used to make, that might make the manufacturer obsolete or incompetent or irrelevant, but in my book it makes the parts become merely unavailable, not obsolete. If they could make something better then the parts would be obsolete, but then we wouldn't be upset about it.
PNPs with high BV_EBO
Started by ●August 8, 2018
Reply by ●August 15, 20182018-08-15
Reply by ●August 15, 20182018-08-15
Chris Jones wrote...> >On 15/08/2018 01:27, pcdhobbs@gmail.com wrote: >> Both also obsolete. :( > >I object to that terminology. > >If a manufacturer is not capable of making, or unwilling to make, or too >inept to sell, something as good as they used to make, that might make >the manufacturer obsolete or incompetent or irrelevant, but in my book >it makes the parts become merely unavailable, not obsolete. > >If they could make something better then the parts would be obsolete, >but then we wouldn't be upset about it.Hear, hear! -- Thanks, - Win
Reply by ●August 15, 20182018-08-15
pcdhobbs@gmail.com wrote...> >> How about cmpt404a, Vebo =3D 25 volts. >> https://www.centralsemi.com/ Active status. >> 5085 stock at Mouser, 10-week factory lead time. > > Thanks, Win. We talked about that one upthread > --it seems to be another of those unique parts > that are dangerous to design with. :(Actually, not very unique at all. These were originally designed as chopper transistors, and used for very low saturation-voltage switches. That's an area that Zetex has put to great use, making a huge line of cheaper BJTs that compete with MOSFET switches for up to 10s of amps. These transistor have high inverting gain, and are designed to be highly symmetrical, so you can exchange the emitter and collector almost without affect. That's why the Veb values are so high. And that's why Vce(sat) is so low, in the forward as well as the inverted modes. There are many uses for transistors made this way, and with a reliable company like Central Semi, they should be here for the long term. -- Thanks, - Win
Reply by ●August 15, 20182018-08-15
> These transistor have high inverting gain, and > are designed to be highly symmetrical, so you > can exchange the emitter and collector almost > without affect. That's why the Veb values are > so high. And that's why Vce(sat) is so low, > in the forward as well as the inverted modes.> There are many uses for transistors made this > way, and with a reliable company like Central > Semi, they should be here for the long term.The 2SD2704K is an NPN version of the same idea, and it sure is useful, I agree. I wouldn't have a big problem characterizing a low-sat transistor for inverted use at higher voltage, though I'd probably do a lifetime buy once the design was done. My trouble is that customers who are producing my designs tend to get queasy about exceeding Absolute Maximum limits from the datasheets. Cheers Phil Hobbs
Reply by ●August 15, 20182018-08-15
On Wednesday, 15 August 2018 11:25:10 UTC+1, pcdh...@gmail.com wrote:> > These transistor have high inverting gain, and > > are designed to be highly symmetrical, so you > > can exchange the emitter and collector almost > > without affect. That's why the Veb values are > > so high. And that's why Vce(sat) is so low, > > in the forward as well as the inverted modes. > > > There are many uses for transistors made this > > way, and with a reliable company like Central > > Semi, they should be here for the long term. > > The 2SD2704K is an NPN version of the same idea, and it sure is useful, I agree. I wouldn't have a big problem characterizing a low-sat transistor for inverted use at higher voltage, though I'd probably do a lifetime buy once the design was done. > > My trouble is that customers who are producing my designs tend to get queasy about exceeding Absolute Maximum limits from the datasheets. > > Cheers > > Phil Hobbsis it the only way?
Reply by ●August 15, 20182018-08-15
On Wednesday, August 15, 2018 at 3:22:02 PM UTC-4, tabb...@gmail.com wrote:> On Wednesday, 15 August 2018 11:25:10 UTC+1, pcdh...@gmail.com wrote: > > > These transistor have high inverting gain, and > > > are designed to be highly symmetrical, so you > > > can exchange the emitter and collector almost > > > without affect. That's why the Veb values are > > > so high. And that's why Vce(sat) is so low, > > > in the forward as well as the inverted modes. > > > > > There are many uses for transistors made this > > > way, and with a reliable company like Central > > > Semi, they should be here for the long term. > > > > The 2SD2704K is an NPN version of the same idea, and it sure is useful, I agree. I wouldn't have a big problem characterizing a low-sat transistor for inverted use at higher voltage, though I'd probably do a lifetime buy once the design was done. > > > > My trouble is that customers who are producing my designs tend to get queasy about exceeding Absolute Maximum limits from the datasheets.> > is it the only way?Not at all--it just saves parts. Low-Z circuits have fewer options, but my PNP is the driver stage of a Sziklai pair so I can just use a 10k resistor and a diode from base to emitter to prevent reverse voltage. (For lurkers: a Sziklai is like a Darlington, but with a PNP driving an NPN, so that the whole thing looks like a single power PNP). Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●August 15, 20182018-08-15
On Wed, 15 Aug 2018 16:03:56 +1000, Chris Jones <lugnut808@spam.yahoo.com> wrote:>On 15/08/2018 01:27, pcdhobbs@gmail.com wrote: >> Both also obsolete. :( > >I object to that terminology. > >If a manufacturer is not capable of making, or unwilling to make, or too >inept to sell, something as good as they used to make, that might make >the manufacturer obsolete or incompetent or irrelevant, but in my book >it makes the parts become merely unavailable, not obsolete.Nonsense. Perhaps it's no longer *profitable* to make?>If they could make something better then the parts would be obsolete, >but then we wouldn't be upset about it.
Reply by ●August 16, 20182018-08-16
On 16/08/2018 12:28, krw@notreal.com wrote:> On Wed, 15 Aug 2018 16:03:56 +1000, Chris Jones > <lugnut808@spam.yahoo.com> wrote: > >> On 15/08/2018 01:27, pcdhobbs@gmail.com wrote: >>> Both also obsolete. :( >> >> I object to that terminology. >> >> If a manufacturer is not capable of making, or unwilling to make, or too >> inept to sell, something as good as they used to make, that might make >> the manufacturer obsolete or incompetent or irrelevant, but in my book >> it makes the parts become merely unavailable, not obsolete. > > Nonsense. Perhaps it's no longer *profitable* to make?As I stated, I was objecting to the terminology. I was not speculating on the profitability of making the parts and selling them at any particular price.
Reply by ●August 16, 20182018-08-16
On Tue, 14 Aug 2018 05:32:32 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote: 2SA1613
Reply by ●August 16, 20182018-08-16
On Thu, 16 Aug 2018 15:36:11 +1000, Chris Jones <lugnut808@spam.yahoo.com> wrote:>On 16/08/2018 12:28, krw@notreal.com wrote: >> On Wed, 15 Aug 2018 16:03:56 +1000, Chris Jones >> <lugnut808@spam.yahoo.com> wrote: >> >>> On 15/08/2018 01:27, pcdhobbs@gmail.com wrote: >>>> Both also obsolete. :( >>> >>> I object to that terminology. >>> >>> If a manufacturer is not capable of making, or unwilling to make, or too >>> inept to sell, something as good as they used to make, that might make >>> the manufacturer obsolete or incompetent or irrelevant, but in my book >>> it makes the parts become merely unavailable, not obsolete. >> >> Nonsense. Perhaps it's no longer *profitable* to make? > >As I stated, I was objecting to the terminology. I was not speculating >on the profitability of making the parts and selling them at any >particular price.Price is only tangentially related to profit. If something isn't making a profit, it's not going to get made. That's all there is to it.
