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High IP3 VHF LNA - RF Cafe Forums
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FrodeS
Post subject: High IP3 VHF LNA Posted: Tue Feb 26, 2008 11:33
am
Lieutenant
Joined: Mon Sep 24, 2007 8:34 am
Posts:
2
Hi,
I am looking for a high dynamic range VHF LNA. The
data should be around:
Gain 15dB
NF: <2dB
OIP3 >30dBm
This is not an easy task. (Perhaps it was easier 30 years ago,
when VHF were a "popular" frequency?) The pHEMTs are great, but have
too much gain at VHF frequencies. Do anyone know if there exist any
chips designed for VHF/UHF, rather than 6GHz - that has good NF and
high OIP3? The most likely solution for me is perhaps to try to make
some kind of transformer feedback configuration in order too meet my
demands. Yet I wonder if that is easier said than done!
Top
frmunder
Post subject: Posted: Thu Feb 28, 2008 3:48 pm
Lieutenant
Joined: Mon Sep 25, 2006 5:52 pm
Posts:
2
SPF-5122Z from Sirenza (now RFMD) may have a too much gain, but
it has a high IP3, low noise figure and is already matched in a small
package.
It has >>+30 IP3, so maybe a pad on the output to
get rid of some gain.
Update: Looking at the spec sheet,
it looks pretty bad at VHF. Gain is way too high and OIP3 falls off.
Posted 11/12/2012
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