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SA58631_15 Datasheet, PDF (17/21 Pages) NXP Semiconductors – 3 W BTL audio amplifier | |||
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NXP Semiconductors
SA58631
3 W BTL audio ampliï¬er
16.4 Reï¬ow soldering
Key characteristics in reï¬ow soldering are:
⢠Lead-free versus SnPb soldering; note that a lead-free reï¬ow process usually leads to
higher minimum peak temperatures (see Figure 23) than a PbSn 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
⢠Reï¬ow temperature proï¬le; this proï¬le includes preheat, reï¬ow (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 classiï¬ed in accordance with
Table 8 and 9
Table 8. SnPb eutectic process (from J-STD-020C)
Package thickness (mm) Package reï¬ow temperature (°C)
Volume (mm3)
< 350
⥠350
< 2.5
235
220
⥠2.5
220
220
Table 9. Lead-free process (from J-STD-020C)
Package thickness (mm) Package reï¬ow 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 reï¬ow
soldering, see Figure 23.
SA58631_2
Product data sheet
Rev. 02 â 12 October 2007
© NXP B.V. 2007. All rights reserved.
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