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In- output impedance 2SC1971 - RF Cafe Forums
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Extreme
Post subject: In- output impedance 2SC1971 Posted: Sun Feb
04, 2007 3:17 pm
Captain
Joined: Sun Feb 04, 2007
2:58 pm
Posts: 9
Hello all,
Just found this forum...very
nice.
For a week now i try to understand the wonder world of micro-strips.
This in combination with the 2SC1971 transistor.
I try a lot in RF-SIM99,and
it works fine.
I just take a few ohm's for the in- and output impedance.
But now i want to try some for real,but i can't find the data for the
transistor.
How do i get the correct impedance from the sheet for
appr. 100MHz
And what would be a acceptabe reflection(dB) for wideband
use.
I can get from the simulations a reflection of maximun -22dB
from 88-108MHz...isthis acceptabe.
I hope to get some info from one
of you
Greetings Bert
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fred47
Post
subject: 2sc1971Posted: Mon Feb 05, 2007 5:34 pm
General
Joined: Wed Feb 22, 2006 3:51 pm
Posts: 104
Hi!
The
2SC1971 data sheet is particularly sparse - I don't think there's enough
information on the copy I found on the web to allow you to use it in
a simulator.
It appears that the device has ceased being manufactured
- do you have a particular reason to use that specific device?
Good Luck,
Fred
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IR
Post subject: Posted:
Tue Feb 06, 2007 4:39 pm
Site Admin
Joined: Mon Jun
27, 2005 2:02 pm
Posts: 373
Location: Germany
I also looked
at the data sheet of this transistor and the main information is missing
i.e. the S-Paramaters.
Therefore, you can't tell what is the
input or output impedance in relation to the frequency. I suggest you
to contact the manufacturer and ask for this data or use an alternative
device which has a data sheet in which S-Parmaters are included.
Good luck!
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Extreme
Post subject: Posted:
Tue Feb 06, 2007 6:30 pm
Captain
Joined: Sun Feb
04, 2007 2:58 pm
Posts: 9
Thanks for the reply's guys.
The
original 2SC1971 from mitshubishi is no more in production.
The ones
now being sold are chinese reproductions,but work just as good.
I
made a design by copying some pieces of the www and adapt the strips
some,until it was as good as flat from 88-108MHz.
And this on single
side board???
Maybe they don't work as a microstrip,but as a low
Q coil.
But my goal was to understand the strips,and make whatever
i want.
And match one transistor to the other,without going to 50ohm
again.
I have a long way to go
Top
fred47
Post subject: microstrip?Posted: Tue Feb 06, 2007 8:55 pm
General
Joined: Wed Feb 22, 2006 3:51 pm
Posts: 104
Hi!
Just a remark, so that you don't go charging off down
the wrong path...
Microstrip is defined as a strip of conductor
above a ground plane, separated by a dielectric. So there is no such
thing as microstrip on a single-sided board. I'm not sure if what you
have would be classified as CPW (co-planar waveguide) or not - I've
never done CPW.
The equations in the books for microstrip won't
do the job for you.
Good Luck!
Fred
Posted 11/12/2012
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