Lpc2000

----- Original Message ----- 
From: "Mark Butcher" <M_J_Butcher@...>
To: <lpc2000@yahoogroups.com>
Sent: Friday, August 26, 2005 11:17 PM
Subject: [lpc2000] LPC2106 Ports (sensitivity to destruction?)


> Hi All
>
> we are using the LPC2106 to read some serial data (among other
> things) from an external device (about 5" away via flat band cable
> in the same equipment driven by 3V3).
>
> During the development we noticed that a couple of prototypes
> stopped working properly and the ports seemed to have been destroyed
> (we couldn't toggle them any more). "May be we applied a high
> voltage or something we decided and, after changing the chip, forgot
> it.
>
> Now we have manufactured about 1000 pieces of equipment and have
> been suprised with the high failure rate in the test. From the
> errors associated with reading the data from the external chip we
> have a high percentage due to failure of ports in the LPC2106 (2..3%
> of batch) - either they don't work or we can measure a low impedance
> short circuit to ground.
>
> We can assume it is not due to handling because their production is
> at a quality production company.
>
> There are a few hundred in the field and we don't know of failures
> after leaving the test field...
>
> There are some other errors which we haven't studied in detail which
> may be concerned with other ports (used for local bit banging), I'll
> know next week once the failure causes are known.
>
> Has any one experience or details about this type of failure or
> possible causes? There are no high voltage involved, the chip it
> reads data from is 3V3 and required only a few uA so what can be
> doing the damage???

Something might be happening when you are connecting the units together. I'd 
be inclined to put something like 3.3 V Transguards (made by AVX) on all the 
lines.

Leon 



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