Re: Spice Models for 2SC4001 and 2SA1546

From: Kevin Aylward (salesEXTRACT_at_anasoft.co.uk)
Date: 10/28/04 

Date: Thu, 28 Oct 2004 12:41:56 GMT

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!

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.