tda8035hn NXP Semiconductors, tda8035hn Datasheet - Page 26

• Manufacturer Part Number: tda8035hn
• Description: Smart Card Interface
• Manufacturer: NXP Semiconductors

NXP Semiconductors
14. Soldering
TDA8035HN
Product data sheet
14.1 Introduction to soldering surface mount packages
14.2 Reflow soldering
14.3 Wave soldering
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 surface mount IC packages. 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.
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 and 200 seconds depending on heating method.
Typical reflow peak temperatures range from 215 to 250 °C. The top-surface temperature
of the packages should preferable be kept below 220 °C for thick/large packages, and
below 235 °C small/thin packages.
Conventional single wave soldering is not recommended for surface mount devices
(SMDs) or printed-circuit boards with a high component density, as solder bridging and
non-wetting can present major problems.
To overcome these problems the double-wave soldering method was specifically
developed.
If wave soldering is used the following conditions must be observed for optimal results:
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
dispensing. The package can be soldered after the adhesive is cured.
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•
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Use a double-wave soldering method comprising a turbulent wave with high upward
pressure followed by a smooth laminar wave.
For packages with leads on two sides and a pitch (e):
– larger than or equal to 1.27 mm, the footprint longitudinal axis is preferred to be
– smaller than 1.27 mm, the footprint longitudinal axis must be parallel to the
The footprint must incorporate solder thieves at the downstream end.
For packages with leads on four sides, the footprint must be placed at a 45° angle to
the transport direction of the printed-circuit board. The footprint must incorporate
solder thieves downstream and at the side corners.
parallel to the transport direction of the printed-circuit board;
transport direction of the printed-circuit board.
All information provided in this document is subject to legal disclaimers.
Rev. 1.0 — 19 April 2011
TDA8035HN
Smart card interface
© NXP B.V. 2011. All rights reserved.
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