Favorite BJT transistors, sot-23 and TO-92 equivalents - I
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From: Okkim Atnarivik on 1 Feb 2010 16:03 John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in > <Okkim.Atnarivik(a)24.fi.invalid> wrote: >>low noise at intermediate frequencies. As an instance, the voltage >>noise of the SiGe BFP650 can be less than 1/4 nanovolt. An example > > Cool. > > Fig 4 is impressive, but "base grounded" implies that it will be > useful only for very low source impedances. Transformers get Current noise is in the ballpark of 4.5 pA/rtHz, which makes it approximately to noise-match with a 50ohm source at an order-of 40K noise temperature. The frequency range extends at least up to 100 MHz but probably still much higher, even with the tranquilizers present. I have had difficulties to wind really wideband transformers on low-loss cores in the past. The sporadic commercial transformers I've tried tended to have to high-enough losses to eat the noise temp. > interesting in such situations, or *lots* of opamps or jfets in > parallel, which will be better at low frequencies. True, done that in the past, with BF862's for instance. It just gets complicated, and in wideband designs you may create curious oscillation modes. In the sub-10kHz you can indeed do better with some other amps. Regards, Mikko
From: Joerg on 1 Feb 2010 16:10 Okkim Atnarivik wrote: [...] > True, done that in the past, with BF862's for instance. ... ^^^^^ Hey, Winfield, Mikko just brought another excellent one for the jelly-bean list. This one has got to be in there, very low pinch-off JFET, steep enough to start an oscillator from less voltage than a fuel cell provides. Very useful. How could I have forgotten, oh, this will haunt me, the wrath of the old Philips engineers will come upon me ... -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Okkim Atnarivik on 1 Feb 2010 16:31 Joerg <invalid(a)invalid.invalid> wrote in news:7soub2Fc5mU1 > Hey, Winfield, Mikko just brought another excellent one for the > jelly-bean list. This one has got to be in there, very low pinch-off > JFET, steep enough to start an oscillator from less voltage than a fuel Yes, but he asked for BJTs...
From: Robert Baer on 2 Feb 2010 06:20 Jim Thompson wrote: > On 31 Jan 2010 10:51:43 -0800, Winfield Hill > <Winfield_member(a)newsguy.com> wrote: > >> Working on a table for our book, soliciting your >> opinions, info and advice. For example, try these: >> >> '3904 ans '3906 = jellybean? > > Absolutely! Probably the most popular general purpose NPN/PNP pair > around. > >> MPS5179, PN5179, MMBT5179 -- what's PNP equivalent? >> >> BC547 NPN, sot-23 equiv = BC847, right? >> BC557 PNP, sot-23 = BC857 ? >> can I just show the C-grade high-beta variant? >> >> '2369 ... what's a better type, PNP equiv? > > '2369 is a gold-doped NPN made for switching purposes (dating to my > youth :-). I don't know of a complement. > >> and etc... >> >> I'm working on two tables, a short one for inclusion >> within the body of the transistor chapter, and a long >> one to be placed at the back of the book. Your >> favorite candidates are solicited. > > Raytheon CK722 ?:-) > > ...Jim Thompson Want a working unit?
From: Jim Thompson on 2 Feb 2010 10:24
On Tue, 02 Feb 2010 03:20:19 -0800, Robert Baer <robertbaer(a)localnet.com> wrote: >Jim Thompson wrote: >> On 31 Jan 2010 10:51:43 -0800, Winfield Hill >> <Winfield_member(a)newsguy.com> wrote: >> >>> Working on a table for our book, soliciting your >>> opinions, info and advice. For example, try these: >>> >>> '3904 ans '3906 = jellybean? >> >> Absolutely! Probably the most popular general purpose NPN/PNP pair >> around. >> >>> MPS5179, PN5179, MMBT5179 -- what's PNP equivalent? >>> >>> BC547 NPN, sot-23 equiv = BC847, right? >>> BC557 PNP, sot-23 = BC857 ? >>> can I just show the C-grade high-beta variant? >>> >>> '2369 ... what's a better type, PNP equiv? >> >> '2369 is a gold-doped NPN made for switching purposes (dating to my >> youth :-). I don't know of a complement. >> >>> and etc... >>> >>> I'm working on two tables, a short one for inclusion >>> within the body of the transistor chapter, and a long >>> one to be placed at the back of the book. Your >>> favorite candidates are solicited. >> >> Raytheon CK722 ?:-) >> >> ...Jim Thompson > Want a working unit? I have several each of CK722, CK760 and CK761 (if I can remember where I stashed them :-). My father was a Raytheon wholesaler from 1956 onward for quite a few years. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |