Multilayer varistors (MLVs)
Automotive series
A further advantage of adhesion is that the components are subjected to virtually no temperature
shock at all. The curing temperatures of the adhesives are between 120 °C and 180 °C, typical
curing times are between 30 minutes and one hour.
The bending strength of glued chips is, in comparison with that of soldered chips, higher by a fac-
tor of at least 2, as is to be expected due to the elasticity of the glued joints.
The lower conductivity of conductive adhesive may lead to higher contact resistance and thus re-
sult in electrical data different to those of soldered components. Users must pay special attention
to this in RF applications.
6
Solderability tests
Test
Standard
Test conditions
Sn-Pb soldering
Test conditions
Pb-free soldering
Criteria/ test results
Covering of 95% of
Wettability
IEC
Immersion in
Immersion in
60068-2-58 60/40 SnPb solder Sn96.5Ag3.0Cu0.5 end termination,
using non-activated solder using non- or checked by visual
flux at 215 ± 3 °C
for 3 ± 0.3 s
low activated flux
at 245 ± 5 °C
for 3 ± 0.3 s
inspection
Leaching
IEC
Immersion in
Immersion in
No leaching of
resistance
60068-2-58 60/40 SnPb
solder using
Sn96.5Ag3.0Cu0.5 contacts
solder using non- or
mildly activated flux low activated flux
without preheating without preheating
at 260 ± 5 °C
for 10 ±1 s
at 255 ± 5 °C
for 10 ±1 s
Thermal shock
(solder shock)
Dip soldering at
300 °C/5 s
Dip soldering at
300 °C/5 s
No deterioration of
electrical parameters.
Capacitance change:
≤ ±15%
Tests of resistance IEC
Immersion in
Immersion in
Change of varistor
to soldering heat
for SMDs
60068-2-58 60/40 SnPb for 10 s Sn96.5Ag3.0Cu0.5 voltage:
at 260 °C
for 10 s at 260 °C
≤ ±5%
Tests of resistance IEC
Immersion
Immersion
of leads in
Sn96.5Ag3.0Cu0.5 Change of
for 10 s at 260 °C capacitance X7R:
≤ ꢁ5/+10%
Change of varistor
voltage: ≤ ±5%
to soldering heat
for radial leaded
components
(SHCV)
60068-2-20 of leads in
60/40 SnPb
for 10 s at 260 °C
Please read Cautions and warnings and
Important notes at the end of this document.
Page 63 of 72
EPCOS [ EPCOS ]
