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

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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


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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