It's not a completely bare die. It has an opaque layer on the top but on
the bottom there are balls attached directly to the die, so the light path
that is affecting it is reflection off the PCB surface, up under the IC and
into its substrate. Dave Jones of EEVblog has a video on it.


On Thu, Mar 19, 2015 at 7:40 AM, <alan.b.pearce@stfc.ac.uk> wrote:

> How can they have a bare die on the PCB? Does it have clear encapsulation=
?
>
> Still, my comments from the previous mail will still apply, any active
> device on there will become a photodiode or phototransistor going into
> hyper conduction with a xenon light flash.
>
>
>
> > -----Original Message-----
> > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behal=
f
> > Of Robert Dvoracek
> > Sent: 19 March 2015 04:56
> > To: Microcontroller discussion list - Public.
> > Subject: RE: [EE] Xenon flashes/long wave high-intensity light causes t=
he
> > Raspberry Pi 2 SMPS chip to glitch
> >
> > Yes, one of the ICs is bare die and light sensitive.
> > A dab of opaque epoxy fixes that in a hurry.
> >
> > Cheers,
> > Robert
> >
> > ----------------------------------------
> > > Date: Thu, 19 Mar 2015 13:48:10 +1000
> > > From: david@audiovisualdevices.com.au
> > > To: piclist@mit.edu
> > > Subject: Re: [EE] Xenon flashes/long wave high-intensity light causes
> > > the Raspberry Pi 2 SMPS chip to glitch
> > >
> > > It is the flash of light and has had coverage in various forums
> > > (EEVblog, etc). IIRC it's the reset chip that is the culprit.
> > >
> > > On 19/03/2015 1:38 PM, Randy Dawson wrote:
> > >> I don't think it is the flash thats causing the micro to glitch, but
> > >> the gnd/voltage spike it sees when the thyristor discharges the flas=
h
> > >> cap (a few hundred volts)
> > >>
> > >>> Date: Wed, 18 Mar 2015 23:44:04 -0300
> > >>> Subject: Re: [EE] Xenon flashes/long wave high-intensity light
> > >>> causes the Raspberry Pi 2 SMPS chip to glitch
> > >>> From: daniel.serpell@gmail.com
> > >>> To: piclist@mit.edu
> > >>>
> > >>> Hi!,
> > >>>
> > >>> On Wed, Mar 18, 2015 at 11:01 PM, V G <veegee@veegee.org> wrote:
> > >>>> http://www.raspberrypi.org/xenon-death-flash-a-free-physics-lesson=
/
> > >>>>
> > >>>> Not sure if this has been posted here before, but I was looking to
> > >>>> buy one of these today and came across this post.
> > >>>
> > >
> > > --
> > > ___________________________________________
> > > David Duffy Audio Visual Devices P/L
> > > Unit 8, 10 Hook St, Capalaba 4157 Australia
> > > Ph: +61 7 38235717 Fax: +61 7 38234717 Our Web Site:
> > > www.audiovisualdevices.com.au
> > > ___________________________________________
> > >
> > > --
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