Re: Westcode Devices
From: Greg Leyh[SMTP:lod-at-pacbell-dot-net]
Sent: Saturday, November 15, 1997 5:37 AM
To: Tesla List
Subject: Re: Westcode Devices
Malcolm Watts wrote:
> Here are the specs for the Westcode devices I mentioned a
> day or two back. See for yourself. A good friend in England managed
> to get them for me.
> ------- Forwarded Message Follows -------
> Those SCRs and diodes are excellent. I will send you the datasheets that
> Westcode FAXed to me today but for the time being, here are a few of the
> specs ( the most relevant ones ). The cost of them wasn't something I
> enquired about, but looking in the RS catalogue shows us a device with
> around a third of the rating at a cost of a hundred quid or thereabouts.
> If you can make sure the dI/dt and dV/dt ratings are not exceeded, you
> may have some near-ideal commutation in the near future.
> dV/dt is 200V/us for off-state rise, to80% of rep. peak voltage
> repetitive dI/dt is 180A/us for a G signal of 20V rising in <1us
> non-rep dI/dt is 300A/us for the same gate criterion
The repetitive dI/dt limit of 180A/us is the limiting factor for this
device. Exceeding this value will produce a puncture on the die next
to the gate structure, caused by secondary breakdown. Otherwise, the
SCR looks great, provided that the primary dI/dt (2*pi*Fpri*Ipeak) is
comfortably less than 180A/us.