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Spice Models for 2SC4001 and 2SA1546

Discussion in 'CAD' started by Kevin Aylward, Oct 27, 2004.

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  1. 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.

    Kevin Aylward

    http://www.anasoft.co.uk
    SuperSpice, a very affordable Mixed-Mode
    Windows Simulator with Schematic Capture,
    Waveform Display, FFT's and Filter Design.
     

  2. Try Class AB, a lot cooler.

    Graham Holloway
    WPS Electronics
     
  3. Ho humm....this was a bit of a joke of course!

    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

    http://www.anasoft.co.uk
    SuperSpice, a very affordable Mixed-Mode
    Windows Simulator with Schematic Capture,
    Waveform Display, FFT's and Filter Design.
     

  4. 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.
     
  5. For a pro audio power amp, i.e. one that can have syths cymbals etc, and
    all sort of stuff, one wants to have full power capability at 20Khz to
    avoid any potential of I.M.D. For example, one might be using a 100W amp
    flat out just for the horns covering say, 3k-20k, in a system of 500W
    for the low end. From a practical point, my view is that the design goal
    is full power at 40Khz to give some margin. Of course, if the amp is
    used with wideband cd music, its unlikely to require full output at 20k,
    but one has to design such that the amp can be used for *any* audio
    application.

    If an amplifier does start triangling at say, 15Khz, its a sure bet that
    that even at lower levels the amp has a fair amount of imd. Fast amps
    and low hf distortion go hand in hand. Its not that you need such a fast
    slew, but those that dont usually have higher distortion.
    This is simply a theoretical exercise.
    I wasn't asking for any. I know how. Its cost that is the issue.

    Kevin Aylward

    http://www.anasoft.co.uk
    SuperSpice, a very affordable Mixed-Mode
    Windows Simulator with Schematic Capture,
    Waveform Display, FFT's and Filter Design.
     
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