Re: [TCML] ESBT Transistors now available in Tesla hobbiest quantities

[Steve Ward <steve.ward@xxxxxxxxx>]

I honestly dont see the benefit, other than the high voltage rating (which
you dont really need).  The current capacity is pretty weak, and the "low"
on resistance aint all that low compared to good mosfets or good IGBTs.

The switching at 150khz sounds highly optimistic given their storage time
(turn off time) being several hundred nS on the one datasheet i looked at.

Powerful SSTCs (or SSTCs of any kind) have to deal with large reactive
currents, so these devices are pitiful when compared to IGBTs that can
effortlessly do 10's to 100's to 1000's of amps and switch just as fast.

Sorry to rain on a parade, but im just giving my opinion: i dont think these
ESBTs are particularly useful for us.  The applications they list (line
operated flyback converter) DOES sound like a great use for them, but that
really doesnt make for a good tesla coil drive, at least not compared to
devices that are currently available in the IGBT and MOSFET variety.

Steve Ward



On Thu, Jan 7, 2010 at 7:37 AM, Bert Pool <micro_wave@xxxxxxxxxxx> wrote:

> A friend of mine sent me an e-mail this week with links to the Mouser site
> on the ESBT, Emitter Switched Bipolar Transistors.  It's my understanding
> that these transistors have been out there about five years, but available
> only if you bought large batches.  Now we can buy them in small quantities
> at very affordable prices. (no, I have no Mouser or STMicro stock   :>)
>
> What do these transistors do for us?
>
> 1) very low "on" resistance, 0.075 ohms
> 2) 8 amps at 1500 volts (there is one version that will do 4 amps at 1700
> volts)
> 3) switching speeds of 150 kilohertz
> 4) price of $8.75 in onesies, $7.70 in lots of 10, $6.30 in lots of 100
>
> Mind you, these are the published maximum ratings - no coiler worth his
> salt would run one with out trying to push it at least 25% to 50% beyond
> those ratings (and a few of you would try way more than that!)
>
> I foresee some very affordable, very powerful SSTC's being built by members
> of this list based upon this technology.
>
> Link to the Mouser catalog page on these parts:
> http://www.mouser.com/Search/Refine.aspx?Keyword=esbt
>
> Link to more information on ESBT transistors and what they are and how they
> work:
> http://www.st.com/search?q=esbt&ud=1&sort=date%3AD%3AL%3Ad1&output=xml_no_dtd&entqr=3&entsp=a&access=p&oe=UTF-8&ie=UTF-8&client=ST_COM_frontend&proxystylesheet=ST_COM_frontend&site=ST_COM
>
> I want to thank Bob Paddock for sharing this info with us.
>
> Bert Pool
>
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