Spice Models for 2SC4001 and 2SA1546

[Kevin Aylward]

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

 

[Graham Holloway]

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.

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

Graham Holloway
WPS Electronics

 

[Kevin Aylward]

Try Class AB, a lot cooler.

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

 

[Graham Holloway]

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.

 

[Kevin Aylward]

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?

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.

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.

This is simply a theoretical exercise.

.I'm sure lots
of suggestions will come in.

I wasn't asking for any. I know how. Its cost that is the issue.

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