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CK727 PNP Si drift transistor - CK766 PNP Ge transistor ratings

L

legg

Jan 1, 1970
0
The data sheet for the CK727 illustrated on the web page:

http://www.ck722museum.com/page7.html

- shows ratings for the part of

5nA (collector current) and
30nW(collector power dissipation).

Please note the units used.

The only other source for data on this part is from the D.A.T.A.
catalog series, that gives collector dissipation of the CK722 as 4mW.

The beta test for this part involves a static collector bias of 10V
and 4mA to establish minimum hfe of 30. This would require the part to
dissipate 40mW, at least for the duration of the test, unless a curve
tracer was used. Even then, this exceeds the paper collector current
rating by some orders of magnitude.

Similar part numbers in similar packages are either rated at

40 to 100mW,

or 2 to 4mW.

Is it possible that the latter group suffer from practitioners
dithering around the same possible typo, made by the same typist, at
around the same time? The typo seems only to affect recorded ratings
for part numbers

CK721 -4mW
CK722 -4mW
CK725 -4mW
CK727 -4mW
CK790 -2mW
CK791 -2mW
CK793 -2mW
all early Si PNP drift types from Raytheon

CK766 -2mW
CK766A -2mW

both early Ge PNP types also from Raytheon

A facsimile of the D.A.T.A. listing is hosted for these parts by
Datasheet Archive, with the first group of four tabulated on the first
page and first lines of the low power silicon pnp transistor section
and the second group in the same location for low power germanium pnp
transistors. The only parts with lower ratings are those with unstated
(blank) listings.

http://www.datasheetarchive.com/search.php?t=0&q=CK766&manystr=&sub.x=34&sub.y=3

http://www.datasheetarchive.com/search.php?t=0&q=CK721&manystr=&sub.x=38&sub.y=5

If this is a typo from the original spec that your sample datasheet
represents, it certainly has gone on for a considerable length of
time.

There should probably be some official notation made, if only for the
sake of museum records, before unprinted reference resources who can
clear it up disappear. I'm sure data for these parts was published and
republished over the years of the part's commercial life.

Anyone with access to other data sources concerning these part numbers
is requested to respond to this news thread or by e-mail to
leggatmagmadotca. I've already contacted Mr Ward for any supplementary
info to which he may also have access.

Anyone with a copy of the IEEE Spectrum magazine of March '03 is also
asked to review it's contents for more relevant information, and to
report it in a similar manner.

Hopefully there will be a more definitive entry available in time for
the new spreadsheet format of bipolar transistor numbers currently in
the works for free distribution on the web.

RL
 
L

legg

Jan 1, 1970
0
Bad scanning. The characters are "m"'s. Hell, those early germanium
things leaked tens of uA. In a lot of cases, the base bias network was
taking current *out* of the base, fighting the leakage that was was
putting it in. One often saw experimenters circuits that just fed
signal into the base through a capacitor.
I don't see bad scanning. Other letters on the identical vertical
axis, including an "m" are uncorrupted, though other instances of m as
n occur elsewhere (enitter and anbient share the same vertical axis)
These look like image format conversion errors due to compression.

Scanning errors are more common on a horizontal (short dimension of
platen), and you can see that in varying text hight and chopped art
detail. The scale and font seems to change between lines, though
constant spacing is preserved between lines.

It doesn't explain 4 or 2mW in the D.A.T.A. source.

What I need is another logo'd data sheet with no errors or different
errors, so that the mfr can claim the new sensible data line in the
spreadsheet.

RL
 
L

legg

Jan 1, 1970
0
First the line...

Both came through ok on this server. Thanks for the help.

The 180mW dissipation is the 25degC ambient extrapolation using the
4mW derating to zero power at 70degC ambient from the 1955 tentative
data. I don't believe that later figures were actually published, as
point contact devices were quickly superceded in industry.
Manufacturers didn't use ambient deratings for long - shifting to case
temperatures PDQ.

At 50deg ambient, that becomes the 80mW rating given on the 1955
tentative data sheet.

RL
 
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