PCA9548A Datasheet, PDF (22/26 Pages) NXP Semiconductors – 8-channel I2C switch with reset

NXP Semiconductors
PCA9548A
8-channel I²C-bus switch with reset
13.4 Reflow soldering
Key characteristics in reflow soldering are:
• Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see Figure 21) than a SnPb process, thus
reducing the process window
• Solder paste printing issues including smearing, release, and adjusting the process
window for a mix of large and small components on one board
• Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature) and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joints (a solder paste
characteristic). In addition, the peak temperature must be low enough that the
packages and/or boards are not damaged. The peak temperature of the package
depends on package thickness and volume and is classified in accordance with
Table 9 and 10
Table 9. SnPb eutectic process (from J-STD-020C)
Package thickness (mm) Package reflow temperature (°C)
Volume (mm³)
< 350
≥ 350
< 2.5
235
220
≥ 2.5
220
220
Table 10. Lead-free process (from J-STD-020C)
Package thickness (mm) Package reflow temperature (°C)
Volume (mm³)
< 350
350 to 2000
< 1.6
260
260
1.6 to 2.5
260
250
> 2.5
250
245
> 2000
260
245
245
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see Figure 21.
PCA9548A_3
Product data sheet
Rev. 03 — 7 July 2009
© NXP B.V. 2009. All rights reserved.
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