SC16C2550 Philips Semiconductors, SC16C2550 Datasheet - Page 42

• Manufacturer Part Number: SC16C2550
• Description: Dual UART with 16 bytes of transmit and receive FIFOs and infrared (IrDA) encoder/decoder
• Manufacturer: Philips Semiconductors

Philips Semiconductors
12. Soldering
9397 750 11621
Product data
12.2.1 Soldering by dipping or by solder wave
12.2.2 Manual soldering
12.3.1 Reflow soldering
12.1 Introduction
12.2 Through-hole mount packages
12.3 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 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.
Typical dwell time of the leads in the wave ranges from 3 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
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.
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 and 400 C, contact may be up to 5 seconds.
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 270 C depending on solder
paste material. The top-surface temperature of the packages should preferably be
kept:
•
below 220 C (SnPb process) or below 245 C (Pb-free process)
– for all the BGA and SSOP-T packages
Dual UART with 16 bytes of transmit and receive FIFOs and IrDA
Rev. 03 — 19 June 2003
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
SC16C2550
encoder/decoder
stg(max)
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