Winfield Hill wrote:> Gerhard Hoffmann wrote... >> >> Am 21.12.2017 um 21:07 schrieb LM: >>> Has anyone seen a NPN bipolar transistor with emitter in >>> the middle, tab. Emitter is easier to ground in RF amplifiers. >> >> Yes. >> Infineon BFQ790. > > And Mini-Circuits wideband RF amplifiers, that come in 3-pin > SOT-89 packages, with an inductor to the supply bus, 50-ohm > IN and 50-ohm OUT, have their tab and middle pin grounded. > >What is wrong with grounded base?
A SOT-89 with emitter in the middle
Started by ●December 21, 2017
Reply by ●December 24, 20172017-12-24
Reply by ●December 24, 20172017-12-24
On Thu, 21 Dec 2017 23:51:23 +0200, LM <sala.nimi@mail.com> wrote:>On Thu, 21 Dec 2017 21:55:23 +0100, Gerhard Hoffmann ><ghf@hoffmann-hochfrequenz.de> wrote: > >>Am 21.12.2017 um 21:07 schrieb LM: >>> Has anyone seen a NPN bipolar transistor with emitter in the middle, >>> tab. Emitter is easier to ground in RF amplifiers. >>> >> >>Yes. >> >>Infineon BFQ790. >> >>regards, Gerhard >> >Good. Digikey has it. Then read long "Absolute Maximum Ratings" list >and began to wonder. BFQ790 is a bit delicate and too fast for my >applicationas as <1GHZ amplifier"Too fast?" Excuse me, but I don't understand those words. -- John Larkin Highland Technology, Inc trk jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●December 24, 20172017-12-24
John Larkin wrote:> On Thu, 21 Dec 2017 23:51:23 +0200, LM <sala.nimi@mail.com> wrote: > >> On Thu, 21 Dec 2017 21:55:23 +0100, Gerhard Hoffmann >> <ghf@hoffmann-hochfrequenz.de> wrote: >> >>> Am 21.12.2017 um 21:07 schrieb LM: >>>> Has anyone seen a NPN bipolar transistor with emitter in the middle, >>>> tab. Emitter is easier to ground in RF amplifiers. >>>> >>> >>> Yes. >>> >>> Infineon BFQ790. >>> >>> regards, Gerhard >>> >> Good. Digikey has it. Then read long "Absolute Maximum Ratings" list >> and began to wonder. BFQ790 is a bit delicate and too fast for my >> applicationas as <1GHZ amplifier > > "Too fast?" Excuse me, but I don't understand those words. > >Maybe "too fast" means the data was received before it was sent...
Reply by ●December 25, 20172017-12-25
On Sun, 24 Dec 2017 18:27:04 -0800, Robert Baer <robertbaer@localnet.com> wrote:>John Larkin wrote: >> On Thu, 21 Dec 2017 23:51:23 +0200, LM <sala.nimi@mail.com> wrote: >> >>> On Thu, 21 Dec 2017 21:55:23 +0100, Gerhard Hoffmann >>> <ghf@hoffmann-hochfrequenz.de> wrote: >>> >>>> Am 21.12.2017 um 21:07 schrieb LM: >>>>> Has anyone seen a NPN bipolar transistor with emitter in the middle, >>>>> tab. Emitter is easier to ground in RF amplifiers. >>>>> >>>> >>>> Yes. >>>> >>>> Infineon BFQ790. >>>> >>>> regards, Gerhard >>>> >>> Good. Digikey has it. Then read long "Absolute Maximum Ratings" list >>> and began to wonder. BFQ790 is a bit delicate and too fast for my >>> applicationas as <1GHZ amplifier >> >> "Too fast?" Excuse me, but I don't understand those words. >> >> > Maybe "too fast" means the data was received before it was sent...If the CRC comes in first, you can check it before the data arrives and save time. -- John Larkin Highland Technology, Inc trk jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●December 26, 20172017-12-26
John Larkin wrote...> > Unfortunately, SOT89 RF transistors get discontinued > a lot faster than they get introduced. I designed a > wonderful circuit recently, that uses BFQ149s (PNP) > parts, and then they were discontinued. Bummer. We > bought 11,000 to tide us over for a while, but I'm > going to have to redesign eventually.OK, I'll bite. What's the wonderful design that'll swallow up 11,000 BFQ149s, and come back for more? -- Thanks, - Win
Reply by ●December 26, 20172017-12-26
On 26 Dec 2017 05:34:03 -0800, Winfield Hill <hill@rowland.harvard.edu> wrote:>John Larkin wrote... >> >> Unfortunately, SOT89 RF transistors get discontinued >> a lot faster than they get introduced. I designed a >> wonderful circuit recently, that uses BFQ149s (PNP) >> parts, and then they were discontinued. Bummer. We >> bought 11,000 to tide us over for a while, but I'm >> going to have to redesign eventually. > > OK, I'll bite. What's the wonderful design that'll > swallow up 11,000 BFQ149s, and come back for more?It's the output stage of a pulse generator. One of my nearly lifelong hobbies is designing pulse gen output stages. Logic level in, 50 ohm out, programmable Vhi and Vlo, fast, clean, tough, low power dissipation. When I filnally had a really good one, the BFQ149 went EOL. It annoyed me enough that I bought $5000 worth of PNPs so I don't need to redesign it soon. -- John Larkin Highland Technology, Inc trk jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●December 26, 20172017-12-26
On 12/26/2017 11:43 AM, John Larkin wrote:> On 26 Dec 2017 05:34:03 -0800, Winfield Hill > <hill@rowland.harvard.edu> wrote: > >> John Larkin wrote... >>> >>> Unfortunately, SOT89 RF transistors get discontinued >>> a lot faster than they get introduced. I designed a >>> wonderful circuit recently, that uses BFQ149s (PNP) >>> parts, and then they were discontinued. Bummer. We >>> bought 11,000 to tide us over for a while, but I'm >>> going to have to redesign eventually. >> >> OK, I'll bite. What's the wonderful design that'll >> swallow up 11,000 BFQ149s, and come back for more? > > It's the output stage of a pulse generator. > > One of my nearly lifelong hobbies is designing pulse gen output > stages. Logic level in, 50 ohm out, programmable Vhi and Vlo, fast, > clean, tough, low power dissipation. When I filnally had a really good > one, the BFQ149 went EOL. > > It annoyed me enough that I bought $5000 worth of PNPs so I don't need > to redesign it soon. > >As a Christmas present from Broadcom, I got an EOL notice for the ATF55143, a very nice small E-pHEMT. It's sort of an enhancement-mode version of the ATF38143. Thanks a bunch, Broadcom. 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 ●December 26, 20172017-12-26
On Tue, 26 Dec 2017 13:03:52 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 12/26/2017 11:43 AM, John Larkin wrote: >> On 26 Dec 2017 05:34:03 -0800, Winfield Hill >> <hill@rowland.harvard.edu> wrote: >> >>> John Larkin wrote... >>>> >>>> Unfortunately, SOT89 RF transistors get discontinued >>>> a lot faster than they get introduced. I designed a >>>> wonderful circuit recently, that uses BFQ149s (PNP) >>>> parts, and then they were discontinued. Bummer. We >>>> bought 11,000 to tide us over for a while, but I'm >>>> going to have to redesign eventually. >>> >>> OK, I'll bite. What's the wonderful design that'll >>> swallow up 11,000 BFQ149s, and come back for more? >> >> It's the output stage of a pulse generator. >> >> One of my nearly lifelong hobbies is designing pulse gen output >> stages. Logic level in, 50 ohm out, programmable Vhi and Vlo, fast, >> clean, tough, low power dissipation. When I filnally had a really good >> one, the BFQ149 went EOL. >> >> It annoyed me enough that I bought $5000 worth of PNPs so I don't need >> to redesign it soon. >> >> >As a Christmas present from Broadcom, I got an EOL notice for the >ATF55143, a very nice small E-pHEMT. It's sort of an enhancement-mode >version of the ATF38143. > >Thanks a bunch, Broadcom. > >Cheers > >Phil HobbsThe ephemts are wonderful, and I worry about them too. Gabe, an Avago ephemt guy, lives across the street. I'll ask him for an honest opinion about the status of those parts. There are a couple of new players in the fast bipolar biz, like Rohm and Toshiba and ON. But the newish stuff is mostly SOT23 and NPN. So we're back to all-NPN design. -- John Larkin Highland Technology, Inc trk jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●December 27, 20172017-12-27
John Larkin wrote...> Winfield Hill wrote: >> John Larkin wrote... >>> >>> Unfortunately, SOT89 RF transistors get discontinued >>> a lot faster than they get introduced. I designed a >>> wonderful circuit recently, that uses BFQ149s (PNP) >>> parts, and then they were discontinued. Bummer. We >>> bought 11,000 to tide us over for a while, but I'm >>> going to have to redesign eventually. >> >> OK, I'll bite. What's the wonderful design that'll >> swallow up 11,000 BFQ149s, and come back for more? > > It's the output stage of a pulse generator. ...I checked, there's virtually no BFQ149 stock available. When the inventory disappears that fast, it means, or it should have meant to NXP, the demand really wasn't low enough to justify a sharp product discontinuation. (There are other solutions, they could have increased the price and waited a few years, or made a mass of product and deposited it with Rochester, etc.) I think that a bean counter, imagining greater profits by radically trimming a product line, isn't taking into account the ultimate losses that will result from the bad effects of his breaking faith with the engineering community designing in his products in the first place. -- Thanks, - Win
Reply by ●December 27, 20172017-12-27
On 27 Dec 2017 05:50:29 -0800, Winfield Hill <hill@rowland.harvard.edu> wrote:>John Larkin wrote... >> Winfield Hill wrote: >>> John Larkin wrote... >>>> >>>> Unfortunately, SOT89 RF transistors get discontinued >>>> a lot faster than they get introduced. I designed a >>>> wonderful circuit recently, that uses BFQ149s (PNP) >>>> parts, and then they were discontinued. Bummer. We >>>> bought 11,000 to tide us over for a while, but I'm >>>> going to have to redesign eventually. >>> >>> OK, I'll bite. What's the wonderful design that'll >>> swallow up 11,000 BFQ149s, and come back for more? >> >> It's the output stage of a pulse generator. ... > > I checked, there's virtually no BFQ149 stock available. > When the inventory disappears that fast, it means, or > it should have meant to NXP, the demand really wasn't > low enough to justify a sharp product discontinuation. > (There are other solutions, they could have increased > the price and waited a few years, or made a mass of > product and deposited it with Rochester, etc.) > > I think that a bean counter, imagining greater profits > by radically trimming a product line, isn't taking into > account the ultimate losses that will result from the > bad effects of his breaking faith with the engineering > community designing in his products in the first place.Or perhaps the fab the part was run on was being phased out and it wasn't worth the cost of moving it to another fab. Such things happen, particularly when companies are trying to figure out what to do with acquisitions/spin-offs.
