At 05:48 PM 6/11/2008, you wrote:
>Spehro Pefhany wrote:
> >> The load will be up to ~250mA, btw.
> >
> > Use Bob's method only. Eg.
> >
> > R1 1K 1/4W
> > R2 10K
> > R3 6K8
> > NPN: 2N/MMBT4401
> > PNP: 2N/MMBT4403
>
>You had better make sure the load will use all its available voltage else
>the PNP transistor will fry.

What is that supposed to mean? None of the high-side drivers presented
are short-circuit proof.

>  Note that the MMTB4403 can only handle 500mV
>accross it at 250mA.  This circuit will also be quite slow turning off, but
>that may not matter.

?? 'Handle 500mV accross' it?   You talking about SOA? Static Pd(max) at Ta?

'Quite slow' turn-off? tf will be << 1usec.

Where is Olin, and what have you done with him?

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com



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