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From: "Helmut Sennewald"
Subject: Re: Q. medium-power RF transistor
Date: Sun, 10 Nov 2002 00:21:04 +0100
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
"Helmut Sennewald" schrieb im Newsbeitrag
> "Winfield Hill" schrieb im Newsbeitrag
> > email@example.com (carltons) wrote...
> > >
> > > Helmut Sennewald HelmutSennewald@t-online.de wrote:
> > >
> > >> Winfield Hill schrieb ...
> > >>> I'm thinking about making 20 to 30V pulses with a
> > >>> 1ns max risetime into a 50-ohm line...
> > >>>
> > >>> What's a good low-capacitance transistor to use with
> > >>> say Vceo 30V, 500mA capable (h_fe >10 at 500mA) and
> > >>> with f_T of at least say 1GHz at Ic 200mA, Vce 15V?
> > >>
> > >> Hello Win,
> > >> I would try four cascodes in parallel with BFG135 transistors.
> > >> http://www.semiconductors.philips.com/pip/BFG135.html
> > >> The product of output capacitance of your transistor(s) and
> > >> the load (50Ohm) has to be below the wanted rise time.
> > That's a nice transistor, reasonable beta at 100mA, with just
> > over 3pF of Ccb+Coe capacitance. I could parallel four with
> > a 50-ohm pullup to 25V (each in common-base mode, Vcbo = 25V),
> > and still have RC under 1ns. And it looks easy to get.
> > But I wonder, where have all the medium-current 25+ volt RF
> > transistors gone? All the likely parts I have examined are
> > discontinued. For example, an ON Semi MRF3010 or MRF134 RF
> > MOSFET (65V, 1A, Coss + Crss < 12pF) would have been nice a
> > few years ago. What's the ticket now?
> Hello Win,
> I have looked in my archive about my older contributions
> and found the links to the RF-Power Mosfet.
> Hopefully I could help you.
> Best Regards
> ---- Original text
> follows ----------------------------------------------------
> NG: sci.electronics.cad
> Date: 20.3.2002
> Thread: Re: high speed power mosfet models
> Hello Steve,
> Take a first look here as Mohi already recommended,
> and choose the replacement part. Then go to their part and take
> the appropriate SPICE model from Polyfet.
> Motorola seems to have only special models for the HF simulation
> tools ADS, APLAC and AWR and these are not SPICE based simulators as I
> So it looks bad, but what about asking Motorola and tell us what they
> Some general info from ST:
I forgot one of my newer links to power mosfets:
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