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Copyright: 1996 - 2024
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    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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TRANSISTOR FOR EFFICIENT 900 MHz, 100mW PA ? - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. If the folks at phpBB would release a version with integrated sign-in from the major social media platforms, I would resurrect the RF Cafe Forums, but until then it is probably not worth the effort. Regardless, there are still lots of great posts in the archive that ware worth looking at.

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STEVER
Post subject: TRANSISTOR FOR EFFICIENT 900 MHz, 100mW PA ?
Unread postPosted: Thu Sep 02, 2004 6:59 am

Any suggestions 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
Bandwidth: Narrowband
Class: Probably C or harmonic terminated etc (need best efficiency)
Efficiency: Target of better than 60%
Transistor type: Fet or Bipolar
Size: Small parts preferred
Cost: Not critical


Top


GUEST
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.


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GUEST
Post subject: 100 mW amp
Unread postPosted: Sat Sep 11, 2004 9:03 am

Don't know if this is better, the efficiency may be a bit off,
but talk about simple...

[url]http://www.semiconductors.philips.com/acrobat/datasheets/BGA6589_1.pdf
[/url]


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Guest - IFX
Post subject:
Unread postPosted: Sat Sep 11, 2004 11:42 pm

Dear Guest,

Use 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


Datasheet:

http://www.infineon.com/cmc_upload/docu ... bfp450.pdf


Application Notes:

http://www.infineon.com/cmc_upload/migr ... pli026.pdf

More Info:


http://www.infineon.com/cgi/ecrm.dll/ec ... ?oid=13759


If you need more gain add BFP420 / BFP 520 / BFP 620 as a driver to your +20dBm PA.


With Best Regards,

Guest - IFX


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STEVE
Post subject:
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!

Thanks again anyway



Posted  11/12/2012
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