The data sheet for the CK727 illustrated on the web page:
- 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.
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