[sdiy] 2N vs PN vs MPS, etc

[cheater cheater]

Neat! Good to know.

I wonder what great stuff you could find in that transistor book of yours...


D.

On Thu, Oct 8, 2009 at 5:32 PM, Paul Schreiber <synth1 at airmail.net> wrote:
> Back in the "good old days" (when my TRS-80 booted in 2 seconds), there was
> a government group called JDEC, that hat a transistor spec called JANTX (I
> think that meant Joint Army-Navy Transistor Spec).
>
> There were literally 10s of thousands of transistors available. So, what the
> "industry" did is register the spec, and these guys were the "keepers of the
> spec". They assigned the '2N' numbers, so that a 2N2222 from Fairchild was
> *identical* to a 2N2222 from Motorola. Simple enough.
>
> Then, both Motorola and Fairchild started to get 'cute'. They decided to
> market "equivalent" parts. Not the SAME part: an 'equivalent' part. What the
> hell did THAT mean? It meant "We don't want to pay the JAN commitee to keep
> the spec". So, they mape parts like this:
>
> 2N2222A: JAN part, it will cost you 8 cents
> MPS2222A our 'equivalent' part, it is only 6 cents!!!!
>
> Then TI jumped in with TIS parts (like the TIS97 used in RA Minimoogs). It
> was a nightmare for designers.
>
> PN is what Fairchild callled their non-JAN FETs. In most cases, it is the
> *SAME DIE*. What is changed is the *SCREENING*. For example, a JAN
> transistor part would have beta specified over 3 different collector
> currents, over the full temp range. A 'MPS' (Motorola Plastic Semiconductor)
> part is only 25C speced. That sort of thing. The also screwd with the Vce
> specs. Many JAN parts were 60V, but most big users  (like Tandy) were
> turning on 5V stuff so the MPS parts were low voltage, like 30V.
>
> Paul S.
> /has *hardbound* TI transistor databook on shelf, as many pages as a Mouser
> catalog but weighs more
>
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