TDA8757 Datasheet, PDF (33/37 Pages) NXP Semiconductors – Triple 8-bit ADC 170 Msps

Philips Semiconductors
TDA8757
Triple 8-bit ADC 170 Msps
15. Handling information
Inputs and outputs are protected against electrostatic discharge in normal handling.
However, to be completely safe, it is desirable to take normal precautions appropriate
to handling integrated circuits.
16. Soldering
9397 750 09457
Preliminary data
16.1 Introduction to soldering surface mount packages
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.
16.2 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 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.
16.3 Wave soldering
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:
• 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
parallel to the transport direction of the printed-circuit board;
– smaller than 1.27 mm, the footprint longitudinal axis must be parallel to the
transport direction of the printed-circuit board.
Rev. 07 — 28 February 2002
© Koninklijke Philips Electronics N.V. 2002. All rights reserved.
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