NXP Semiconductors
PCK953
20 MHz to 125 MHz PECL input, 9 CMOS output, 3.3 V PLL clock driver
• Package footprints, including solder thieves and orientation
• The moisture sensitivity level of the packages
• Package placement
• Inspection and repair
• Lead-free soldering versus SnPb soldering
14.3 Wave soldering
Key characteristics in wave soldering are:
• Process issues, such as application of adhesive and flux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are
exposed to the wave
• Solder bath specifications, including temperature and impurities
14.4 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 8) 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
PCK953_5
Product data sheet
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.
Rev. 05 — 9 October 2008
© NXP B.V. 2008. All rights reserved.
11 of 15