Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: TRANSISTOR FOR EFFICIENT 900 MHz, 100mW PA
Unread postPosted: Thu Sep 02, 2004 6:59 am
on a nice transistor for a PA at 900MHz with good efficiency? Spec:-
Pout: 50 to 100 mW
Supply rail: 3 Volts
Frequency: 900 MHz
Class: Probably C or harmonic terminated etc
(need best efficiency)
Efficiency: Target of better than 60%
type: Fet or Bipolar
Size: Small parts preferred
Cost: Not critical
Post subject: Any suggestions on a
nice transistor for a PA at 900MHz with
Unread postPosted: Thu Sep
09, 2004 2:08 pm
I've had some great luck with an Infineon BFP450
at those levels, efficiencies and frequencies. Hint
use a constant
current source bias.
100 mW amp
Unread postPosted: Sat Sep 11, 2004 9:03 am
know if this is better, the efficiency may be a bit off,
Guest - IFX
postPosted: Sat Sep 11, 2004 11:42 pm
only Infineon BFP450 for your application. It is very stable and easy
to tune to 900MHz.
It is a SiGe Device with Ft of 25GHz
If you need more gain add BFP420 / BFP 520
/ BFP 620 as a driver to your +20dBm PA.
With Best Regards,
Guest - IFX
Unread postPosted: Mon Sep 13, 2004 9:12 am
Thanks to you all,
Strange (or maybe not) but I ended up prototyping a BFP450 amp last
week. Performance is reasonable without trying very hard (circa 45 to
50% collector eff') but quite a bit harder to get any more efficiency
than that. I tried a harmonic termination of 2F and then 3F but this
did not gain me much for quite a bit more complexity!
again anywayPosted 11/12/2012