CLP200M_03 Datasheet, PDF (17/21 Pages) STMicroelectronics – OVERVOLTAGE AND OVERCURRENT PROTECTION FOR TELECOM LINE

CLP200M
SOLDERING RECOMMENDATION
surface mount devices. Such voids under the
The soldering process causes considerable ther- ^{package result in poor thermal contact and the}
mal stress to a semiconductor component. This ^{high thermal resistance leads to component fail-}
has to be minimized to assure a reliable and ex- ^{ures. The PowerSO-10 is designed from scratch to}
tended lifetime of the device. The PowerSO-10^{TM be solely a surface mount package, hence symme-}
package can be exposed to a maximum tempera- ^{try in the x- and y-axis gives the package excellent}
ture of 260°C for 10 seconds. However a proper ^{weight balance. Moreover, the PowerSO-10 offers}
soldering of the package could be done at 215°C ^{the unique possibility to control easily the flatness}
for 3 seconds. Any solder temperature profile ^{and quality of the soldering process. Both the top}
should be within these limits. As reflow techniques ^{and the bottom soldered edges of the package are}
are most common in surface mounting, typical ^{accessible for visual inspection (soldering menis-}
heating profiles are given in Figure 1,either for ^cus).
mounting on FR4 or on metal-backed boards. For ^{Coplanarity between the substrate and the pack-}
each particular board, the appropriate heat profile ^{age can be easily verified. The quality of the solder}
has to be adjusted experimentally. The present ^{joints is very important for two reasons : (I) poor}
proposal is just a starting point. In any case, the fol- ^{quality solder joints result directly in poor reliability}
lowing precautions have to be considered :
and (II) solder thickness affects the thermal resis-
tance significantly. Thus a tight control of this pa-
- always preheat the device
- peak temperature should be at least 30 °C
) ^{higher than the melting point of the solder}
t(s ^{alloy chosen}
- thermal capacity of the base substrate
c _{Voids pose a difficult reliability problem for large}
du _{Fig 1 : Typical reflow soldering heat profile}
Pro _{Temperature (}o_C)
lete ²⁵⁰
245^oC
rameter results in thermally efficient and reliable
solder joints.
bso ₂₀₀
215^oC
t(s) ^{- O} ₁₅₀
Epoxy FR4
board
roduc ₁₀₀
Soldering
Preheating
lete ^{P Metal-backed}
Obso ⁵⁰
board
Cooling
0
0 40 80 120 160 200 240 280 320 360
Time (s)
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