In- Output Impedance 2SC1971 - RF Cafe Forums
Post subject: In- output impedance 2SC1971 Posted: Sun
Feb 04, 2007 3:17 pm
Joined: Sun Feb
04, 2007 2:58 pm
Just found this
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.
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
I hope to get some info from one
Post subject: 2sc1971Posted: Mon Feb 05, 2007 5:34 pm
Joined: Wed Feb 22, 2006 3:51 pm
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
Post subject: Posted: Tue Feb 06, 2007 4:39 pm
Joined: Mon Jun 27, 2005 2:02 pm
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.
Post subject: Posted: Tue Feb 06,
2007 6:30 pm
Joined: Sun Feb 04, 2007
Thanks for the reply's guys.
2SC1971 from mitshubishi is no more in production.
The ones now
being sold are chinese reproductions,but work just as good.
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
Post subject: microstrip?Posted: Tue
Feb 06, 2007 8:55 pm
Joined: Wed Feb
22, 2006 3:51 pm
Just a remark, so
that you don't go charging off down the wrong path...
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.
in the books for microstrip won't do the job for you.