Hitachi AP1 Data Book page 19

--------------------------------------------------INTRODUCTIONOFPACKAGES
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4. Mounting Method
Package lead pins are surface treated with solder coating or
plating to facilitate PCB mounting. The lead pins are connected
to the package by eutectic solder. Common connecting method
of leads and precautions are explained as follows:
4.1 Mounting Methods of Pin Insertion Type Package
Insert lead pins into the PCB through-holes (usually about
4>0.8mm). Soak leads in a wave solder tub.
Lead pins held by the through-holes enable handling of the
package through the sqldering process, and facilitate automated
soldering. When soldering leads in the wave solder tub, do not
get solder on the package.
4.2 Mounting Method of Surface Mount Type Package
Apply the specified quantity of solder paste to the pattern on
any printed board by the screen printing method, to temporarily
fix the package to the board. The solder paste melts when heated
in a reflowing furnace, and package leads and the pattern of the
printed board are fixed by the surface tension of the melted
solder and self alignment.
The size of the pattern where leads are attached should be 1.1
to 1.3 times the leads' width, depending on paste material or
furnace adjustment.
The temperature of the reflowing furnace is dependent on
packaging material and type. Fig. 2 lists the adjustment of the
reflowing furnace for FPP. Pre-heat the furnace to 150
0
C. Sur-
face temperature of the resin should be kept at 235
0
C maximum
for JO minutes or less.
(I)
The temperature of the leads should be kept at 260° for 10 minutes
or less.
(2) The temperature of the resin should be kept at 235
0
for 10 minutes
or less.
(3) Below is shown the temperature profile when soldering a package
by the reflowing method.
17
'"
"
'"
'"
0.
E
~
Fig.2 Reflowing Furnace Adjustment
for FPP
IUnit:mm)
Time~
Employ adequate heating or temperature control equipment
to prevent damage to the plastic package epoxy-resin material.
When using an infrared heater, avoid long exposure at tempera-
tures higher than the glass transition point of epoxy-resin (about
150 0
C),
which may cause package damage and loss of reliability
characteristics. Equalize the temperature inside and outside of
packages by reducing the heat of the upper surface of the
packages.
FPP leads may easily bend in shipment or during handling,
and impact soldering onto the printed board. Heat the bent leads
again with a soldering iron to reshape them.
Use a rosin flux when SOldering, Do not use chloric flux
because the chlorine in the flux has a tendency to remain on the
leads and reduce reliability. Use alcohol, chlorothene orfreon to
wash away rosin flux from packages. These solvents should not
'remain on the packages for an excessive length of time, because
the package markings may disappear.