Re: Spice Models for 2SC4001 and 2SA1546

From: Graham Holloway (eng_at_wps-electronics.demon.co.uk)
Date: 10/28/04

  • Next message: Kevin Aylward: "Re: Spice Models for 2SC4001 and 2SA1546" 
    Date: Thu, 28 Oct 2004 16:20:36 +0100

    "Kevin Aylward" <salesEXTRACT@anasoft.co.uk> wrote in message
    news:oO5gd.166934$BI5.124558@fe2.news.blueyonder.co.uk...
    > Graham Holloway wrote:
    > > "Kevin Aylward" <salesEXTRACT@anasoft.co.uk> wrote in message
    > > news:a2Tfd.163901$BI5.96135@fe2.news.blueyonder.co.uk...
    > >> Anyone with models for
    > >> 2SC4001 and 2SA1546
    > >>
    > >> I know they are in the purchased topspice:-)
    > >>
    > >> They for my own use, e.g. at ft=300Mhz, 250V, 7W, 3pf makes for a
    > >> good audio amp mosfet driver.
    > >>
    > >> I'd rather not spend the time on making the models, as I'm actually
    > >> working/playing around on a simulated mosfet amp. So far its 500W
    > >> into 8 ohms, at around 1000V/us. It outputs quite a nice square wave
    > >> at 1Mhz, but dissipation per mosfet is a tad high at 1KW.
    > >
    > >
    > > Try Class AB, a lot cooler.
    >
    > Ho humm....this was a bit of a joke of course!

    So was my comment. Although there is a yahoo class A group that would
    welcombe you with open arms, suggestions of water cooling, etc, if you
    should choose that route.

    Most designers of power amplifiers have seen this problem, but I suspect
    they have just decided to compromise on the amount of drive they want to use
    against what constitutes a reasonable upper frequency limit. For example, in
    the case of audio, how much energy is really present at the higher
    frequencies?

    If you really want a 500W square wave at 1MHz you really have no choice but
    to find a way of generating the gate drive. I'm sure lots of suggestions
    will come in.

    >
    > The circuit is in already class B, i.e. as small a bias as possible. It
    > runs fine at 20kz, at 1Mhz its smoking due to switching losses. You need
    > about 2-4A drive to get down to 10ns. This cant be done practically.
    > Anything that gives 1A out, needs around 1A in at 10ns, at these
    > voltages (think "ft" of 100Mhz).
    >
    > Kevin Aylward
    > salesEXTRACT@anasoft.co.uk
    > http://www.anasoft.co.uk
    > SuperSpice, a very affordable Mixed-Mode
    > Windows Simulator with Schematic Capture,
    > Waveform Display, FFT's and Filter Design.
    >
    >

  • Next message: Kevin Aylward: "Re: Spice Models for 2SC4001 and 2SA1546"