What about using NUD3160s?  


--- On Mon, 10/13/08, Olin Lathrop <olin_piclist@embedinc.com> wrote:

> From: Olin Lathrop <olin_piclist@embedinc.com>
> Subject: Re: [EE] Back-EMF catch diodes slowing solenoid response
> To: "Microcontroller discussion list - Public." <piclist@mit.edu>
> Date: Monday, October 13, 2008, 3:50 PM
> tBot wrote:
> > The primary concern
> > is of course to stop burning out my ULN2004A's,
> but limiting release
> > latency would be nice as well.
> 
> First thing I would do is not try driving 1/3 amp with
> something that has as
> high a turn on voltage as a darlington.  You could be
> dissipating 350mW in
> each.  I don't know how many there are per package, but
> add them up and they
> could well exceed the total device power dissipation.
> 
> You could drive a NPN transistor with 10mA base current. 
> At 350mZ collector
> current that requires a minimum gain of 35, which is
> doable.
> 
> As for the snubber, it really should be as close as
> possible to the relay
> coil.  A resistor and diode in series should be fine.  The
> voltage will be
> the diode drop plus the 350mA times the resistance.  With
> 10V reverse on the
> coil, I suspect the current will drop off fast enough that
> going further
> won't make the mechanical relay respond significantly
> faster.
> 
> 
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