tca280b Hendon Semiconductors, tca280b Datasheet - Page 24

• Manufacturer Part Number: tca280b
• Description: General Purpose Triggering Circuit
• Manufacturer: Hendon Semiconductors

Integrated Electronic Solutions, Hendon, South Australia
12 SOLDERING
12.1
There is no soldering method that is
ideal for all IC packages. Wave
soldering is often preferred when
through-hole and surface mounted
components are mixed on one
printed-circuit board. However, wave
soldering is not always suitable for
surface mounted ICs, or for
printed-circuits with high population
densities. In these situations reflow
soldering is often used.
This text gives a very brief insight to a
complex technology. A more in-depth
account of soldering ICs can be found
in our “IC Package Data book” (order
code 9398 652 90011).
12.2
12.2.1
The maximum permissible
temperature of the solder is 260 C;
solder at this temperature must not be
in contact with the joint for more than
5 seconds. The total contact time of
successive solder waves must not
exceed 5 seconds.
The device may be mounted up to the
seating plane, but the temperature of
the plastic body must not exceed the
specified maximum storage
temperature (T
printed-circuit board has been
pre-heated, forced cooling may be
necessary immediately after
soldering to keep the temperature
within the permissible limit.
12.2.2
Apply a low voltage soldering iron
(less than 24 V) to the lead(s) of the
package, below the seating plane or
not more than 2 mm above it. If the
temperature of the soldering iron bit is
less than 300 C it may remain in
contact for up to 10 seconds. If the bit
temperature is between
2002 Nov 08
General purpose triggering circuit
Introduction
DIP
S
WAVE
R
OLDERING BY DIPPING OR BY
EPAIRING SOLDERED JOINTS
stg max
). If the
300 and 400 C, contact may be up to
5 seconds.
12.3
12.3.1
Reflow soldering techniques are
suitable for all SO packages.
Reflow soldering requires solder
paste (a suspension of fine solder
particles, flux and binding agent) to be
applied to the printed-circuit board by
screen printing, stencilling or
pressure-syringe dispensing before
package placement.
Several techniques exist for
reflowing; for example, thermal
conduction by heated belt. Dwell
times vary between
50 and 300 seconds depending on
heating method. Typical reflow
temperatures range from
215 to 250 C.
Preheating is necessary to dry the
paste and evaporate the binding
agent. Preheating duration:
45 minutes at 45 C.
12.3.2
Wave soldering techniques can be
used for all SO packages if the
following conditions are observed:
During placement and before
soldering, the package must be fixed
with a droplet of adhesive. The
adhesive can be applied by screen
printing, pin transfer or syringe
A double-wave (a turbulent wave
with high upward pressure followed
by a smooth laminar wave)
soldering technique should be
used.
The longitudinal axis of the
package footprint must be parallel
to the solder flow.
The package footprint must
incorporate solder thieves at the
downstream end.
SO
R
W
EFLOW SOLDERING
AVE SOLDERING
23
dispensing. The package can be
soldered after the adhesive is cured.
Maximum permissible solder
temperature is 260 C, and maximum
duration of package immersion in
solder is 10 seconds, if cooled to less
than 150 C within 6 seconds. Typical
dwell time is 4 seconds at 250 C.
A mildly-activated flux will eliminate
the need for removal of corrosive
residues in most applications.
12.3.3
Fix the component by first soldering
two diagonally- opposite end leads.
Use only a low voltage soldering iron
(less than 24 V) applied to the flat part
of the lead. Contact time must be
limited to 10 seconds at up to 300 C.
When using a dedicated tool, all other
leads can be soldered in one
operation within 2 to 5 seconds
between 270 and 320 C.
R
EPAIRING SOLDERED JOINTS
TCA280B
Data Sheet