Re: 7704a repair adventure


Back in the day...the -269 was a cut above anything else
in it's class. Compared to most any other transistor
you could find, it had lower C, faster transient response,
low saturation, very linear gain vs current vs voltage
curves. And it really liked to amplify without oscillating.
And it was cheap.
Because of all that, it was a very popular transistor at TEK.

Remember that there are a bunch of time constants in the vertical
to compensate thermal time constants in the devices.

If you can find a pair anywhere else in the scope, or in
some less critical application in a plugin, I suggest you use real
-269s in the vertical and sub the other application that
doesn't show up directly on the screen as vertical deflection.

--- In, "Craig Sawyers" <c.sawyers@t...> wrote:
here are the characteristics:
151-0269-00 - Small signal high speed FMT5092

ft min: 1 GHz @ 5 V/10 mA (Vce/Ic)
hfe: min 30/max 300 @ 10 V/20 mA (Vce/Ic)
Breakdown voltages: Vceo: 15 V, Vcbo: 30 V, Vebo: 4 V
Icbo: 10 nA
Ccb: 1.5 pf
Vce sat: 150 mV/20 mA
Ic max: 80 mA
Case: TO-92
I've just had a browse around, and anything of that spec in a TO92 package
is *very* difficult to find! There is plenty of stuff in surface mount, and
in those little pill-like packages with three or four leads sticking out
radially - but getting that BW out of a discrete TO92 package is very
difficult; it is clearly a very small device, with low Vceo of only 15V and
Ccb of only 1.5pF (presumably including leads).

Try some of the Agilent stuff.


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