TDA8920B_2
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Product data sheet
Rev. 02 — 07 November 2005
29 of 34
Philips Semiconductors
TDA8920B
2
×
100 W class-D power amplifier
16. Soldering
16.1 Introduction
This text gives a very brief insight to a complex technology. A more in-depth account of
soldering ICs can be found in our
Data Handbook IC26; Integrated Circuit Packages
(document order number 9398 652 90011).
There is no soldering method that is ideal for all IC packages. Wave soldering is often
preferred when through-hole and surface mount components are mixed on one
printed-circuit board. Wave soldering can still be used for certain surface mount ICs, but it
is not suitable for fine pitch SMDs. In these situations reflow soldering is recommended.
Driven by legislation and environmental forces the worldwide use of lead-free solder
pastes is increasing.
16.2 Through-hole mount packages
16.2.1 Soldering by dipping or by solder wave
Typical dwell time of the leads in the wave ranges from 3 seconds to 4 seconds at 250
°
C
or 265
°
C, depending on solder material applied, SnPb or Pb-free respectively.
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
stg(max)
). If the
printed-circuit board has been pre-heated, forced cooling may be necessary immediately
after soldering to keep the temperature within the permissible limit.
16.2.2 Manual soldering
Apply the soldering iron (24 V or less) to the lead(s) of the package, either 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 300
°
C and 400
°
C, contact may be up to 5 seconds.
16.3 Surface mount packages
16.3.1 Reflow soldering
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 methods exist for reflowing; for example, convection or convection/infrared
heating in a conveyor type oven. Throughput times (preheating, soldering and cooling)
vary between 100 seconds and 200 seconds depending on heating method.
Typical reflow peak temperatures range from 215
°
C to 270
°
C depending on solder paste
material. The top-surface temperature of the packages should preferably be kept:
•
below 225
°
C (SnPb process) or below 245
°
C (Pb-free process)
– for all BGA, HTSSON..T and SSOP..T packages
