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PCF8594C-2 Datasheet, PDF (16/21 Pages) NXP Semiconductors – 512 X 8-bit CMOS EEPROM with I2C-bus interface | |||
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Philips Semiconductors
PCF8594C-2
512 Ã 8-bit CMOS EEPROM with I2C-bus interface
15. Soldering
9397 750 14221
Product data
15.1 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 ï¬ne pitch SMDs. In these situations reï¬ow soldering is
recommended. Driven by legislation and environmental forces the worldwide use of
lead-free solder pastes is increasing.
15.2 Through-hole mount packages
15.2.1 Soldering by dipping or by solder wave
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 speciï¬ed maximum storage temperature (Tstg(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.
15.2.2 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 and 400 °C, contact may be up to 5 seconds.
15.3 Surface mount packages
15.3.1 Reï¬ow soldering
Reï¬ow soldering requires solder paste (a suspension of ï¬ne solder particles, ï¬ux 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 reï¬owing; 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 reï¬ow 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 225 °C (SnPb process) or below 245 °C (Pb-free process)
â for all the BGA and SSOP-T packages
Rev. 05 â 25 October 2004
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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