BC337 hfe distribution
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From: Jim Thompson on 9 Apr 2010 18:25 On Fri, 9 Apr 2010 22:47:09 +0100, "TTman" <someone.pc(a)ntlworld.com> wrote: > >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in >message news:eq3vr51hn9adhsi5dnqtjpsk1i0rktbpfv(a)4ax.com... >> On Fri, 09 Apr 2010 21:25:45 +0100, John Devereux >> <john(a)devereux.me.uk> wrote: >> >>>"E" <invalid(a)invalid.invalid> writes: >>> >>>> "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> kirjoitti >>>> viestiss�:fmLvn.199280$rq1.66072(a)en-nntp-02.dc1.easynews.com... >>>>> "E" <invalid(a)invalid.invalid> wrote in message >>>>> news:hpnv2c$5it$1(a)news.eternal-september.org... >>>>>> Distribution is a bit strange looking with two spikes >>>>> >>>>> Maybe two different batches of parts? >>>>> >>>> >>>> Possibly, alltought they were all from same bag. >>>> Or maybe just from different wafers? >>>> How many BC337 fit one wafer? Probably quite many... >>>> >>>> -ek >>>> >>>> >>> >>>Perhaps they take all the middle ones for a tighter-spec version? >> >> Roughly 80K _untested_ die (if wafer is 8"). The wafer is probably >> auto-probed and binned into various device numbers. >> >> Discrete device production is so automated... it's fascinating to >> watch the automated handling equipment :-) > >Very true, my brother builds machines that makes the wafers.... > I always was amused by the machines that handle the little "D-shaped" plastic transistors... a shaking machine "tub" causes them to flip over on their heads and "walk" up a ramp, flat side against the wall of the ramp. Then another handlers grabs 'em by the leads and tests and bins them. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: Jim Thompson on 9 Apr 2010 18:40 On Fri, 9 Apr 2010 14:42:29 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"E" <invalid(a)invalid.invalid> wrote in message >news:hpo5sl$l4o$1(a)news.eternal-september.org... >> They have still not managed to get their processes so much under control >> that they can >> make what is needed instead of what happens to come out? > >I think it's more a case of, "for the vast majority of applications, what >comes out is already good enough." Indeed, it makes no sense to try to >tighten up the specs of a 2N2222 since, by the very nature of selecting it for >a design, the designer is saying that tolerances can be quite wide and his >design is still going to work anyway. > >And keep in mind that BJTs have a lot less spread in their device parameters >than FETs anyway. In the simple hybrid-pi small-signal model of a BJT, no >device parameters whatsoever come into play! :-) (...which is not true for >FETs...) You mean none that you recognize. The transistor hybrid-pi model came about before computers and process extraction, thus is strictly an electrical performance model. But I know a guy (Jim Dunkley) who can extract BJT parameters from diffusion profiles. > >At the end of the day I imagine it comes down to cost, though -- if it cost >next to nothing to trim hFE of a 2N2222 to 1%, it would be happening. (Note >that trimming a particular parameter like hFE to 1% *might* imply that you >have to trim various parameters in your process far more tightly -- this is >what can get expensive...) ...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 | The only thing bipartisan in this country is hypocrisy
From: Joel Koltner on 9 Apr 2010 18:57 "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in message news:ucavr5hlkgrvich7dm596kvhn56riofd0f(a)4ax.com... > You mean none that you recognize. Right -- essentially the first BJT model you encounter in school. I realize that while this is a good enough model to design, I dunno, audio amplifiers or oscillators and maybe get a start on a 741, anyone doing BJT-based design today (at least for money :-) ) is using far more sophisticated models that do rely heavily on the actual device parameters.
From: Jim Thompson on 9 Apr 2010 19:15 On Fri, 9 Apr 2010 15:57:28 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in >message news:ucavr5hlkgrvich7dm596kvhn56riofd0f(a)4ax.com... >> You mean none that you recognize. > >Right -- essentially the first BJT model you encounter in school. > >I realize that while this is a good enough model to design, I dunno, audio >amplifiers or oscillators and maybe get a start on a 741, anyone doing >BJT-based design today (at least for money :-) ) is using far more >sophisticated models that do rely heavily on the actual device parameters. > BJT parameters (for Gummel-Poon) are all based on _electrically_ measurable performances. Unlike BJT, CMOS is up into the 60-count of model types developed since the original LEVEL=1 :-) PSpice supports LEVEL=1, 2, 3, 4, 5 (EKVv2.6), 6 (BSIM3v2.0), and 7 (BSIM3v3.2) Other simulators use different numbering conventions... HSpice lists them up to (IIRC) ~ LEVEL=58, never dropping any model numbers that were flops :-) ...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 | The only thing bipartisan in this country is hypocrisy
From: Joel Koltner on 9 Apr 2010 19:32
Hi Jim, "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in message news:cjcvr5prd90rvnu494d5fqu92nh3lgos1n(a)4ax.com... > PSpice supports LEVEL=1, 2, 3, 4, 5 (EKVv2.6), 6 (BSIM3v2.0), and 7 > (BSIM3v3.2) Has that ever been a problem for you, yet -- that PSpice hasn't added any of the newer models? Or do all the foundaries still provide older models even once the new ones are available? > Other simulators use different numbering conventions... HSpice lists > them up to (IIRC) ~ LEVEL=58, never dropping any model numbers that > were flops :-) It looks good to pointy-haired managers when they can say, "We have 58 transistor models, our competitors only have (the) 8 (that are actually used anymore)!" ---Joel |