Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
Subject: Re: FET transistion frequency parameters
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Wed, 4 Dec 2002 19:03:21 -0000
NNTP-Posting-Date: Wed, 04 Dec 2002 19:03:24 GMT
Jim Thompson wrote:
> On Wed, 04 Dec 2002 08:12:23 -0800,
> John Larkin ,
> In Newsgroup: sci.electronics.design,
> Article: ,
> Entitled: "Re: FET transistion frequency parameters",
> Wrote the following:
>> On Wed, 04 Dec 2002 08:08:33 +0000, Paul Burridge
>>> One of my reference books gives all the data on hundreds of
>>> different types of FETS and BJPs. However, I've just noticed that
>>> the column for Ft is simply left blank in respect of every device
>>> that's listed as a FET. Why isn't transition frequency data
>>> published for these devices??
>> Ft is the current-gain-bandwidth product, the frequency where bipolar
>> transistor Hfe (beta) drops to unity. That's meaningless for a fet.
> The critical parameter for gain-bandwidth of CMOS is gmC.
> For analog applications I evaluate a CMOS process by biasing a
> diode-connected CMOS device with a current source, and insert my
> LoopGain part (see my website) between the drain and gate.
> I then do GBW simulations (.AC) with varying bias currents.
Nah....just make minimum size nmos/pmos inverter gain amp an see what
its gain with frequency is over supply volts.
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.