dm00074990

TN0973
Technical note
Safety application guide for SPC56EL54xx, SPC56EL60xx and
RPC56EL60xx family reference manual addendum
Introduction
This document is an addendum of SPC56EL54xx/SPC56EL60xx/RPC56EL60xx Safety
Application Guide.
March 2016
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Contents
TN0973
Contents
1
Purpose and scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Considerations on SPC56EL54xx, SPC/RPC56EL60xx package and
soldering procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
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2.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2
Risk analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.1
Risk item . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.2
Cause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.3
Risk evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.4
Item Assumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
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Purpose and scope
Purpose and scope
The purpose of this document is to communicate to ST customers who intend to integrate
SPC56EL54xx/SPC56EL60xx/RPC56EL60xx in an ASIL-D Item some additional
assumptions which shall be met at item level to preserve the
SPC56EL54xx/SPC56EL60xx/RPC56EL60xx integrity. The assumptions described in this
document shall be intended as additional assumptions with respect to those communicated
in the SPC56EL54xx/SPC56EL60xx/RPC56EL60xx Safety Application Guide.
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Considerations on SPC56EL54xx, SPC/RPC56EL60xx package and soldering procedures TN0973
2
Considerations on SPC56EL54xx, SPC/RPC56EL60xx
package and soldering procedures
2.1
Introduction
SPC56EL54xx/SPC56EL60xx/RPC56EL60xx package is composed by Ultra Low Alpha
mold compound. Measurements report an alpha particle emissivity of 0.00383 ± 0.00056
cp/h/cm2.
This value has been used in the SPC56EL54xx/SPC56EL60xx/RPC56EL60xx quantitative
safety analyses (see SPC56EL54xx/SPC56EL60xx/RPC56EL60xx FMEDA).
In order to ensure that this value does not increase when soldering the device on a board, a
risk analysis is made in the following chapter. The conclusions of this analysis report that
caution must be taken during soldering process in order to avoid package delamination,
hence avoiding any contamination from the soldering material to the silicon contained in the
plastic package.
2.2
Risk analysis
2.2.1
Risk item
Single Event Upset randomly induced by alpha particle emission from Package material
2.2.2
Cause
A possible cause of silicon contamination is the presence of potentially alpha-emissive
soldering material, specifically induced by Pb impurities.
2.2.3
Risk evaluation
Assuming that no delamination is present on the package and given the low migration
capability of Pb particles, the risk of having emissive material on the silicon surface is very
low.
2.2.4
Item Assumption
We recommend our customers to avoid active soldering flux and to verify the integrity of
packages after board mounting in order to eliminate the possibilit y of package delamination
after device mounting on board, therefore eliminating the possibility of silicon contamination
by soldering material.
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Revision history
Revision history
Table 1. Document revision history
Date
Revision
Changes
14-Feb-2013
1
Initial release.
17-Sep-2013
2
Updated Disclaimer.
15-Mar-2016
3
Added RPC56EL60xx device family.
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TN0973
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