PCF8553DTTSLASHA datasheet(41/51 Pages) NXP

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NXP Semiconductors

PCF8553

40 × 4 LCD segment driver

• Package placement

• Inspection and repair

• Lead-free soldering versus SnPb soldering

19.3 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

19.4 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 29) 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 21 and Table 22

Package reflow temperature (°C)

Volume (mm³)

Package thickness (mm)

< 350

≥ 350

< 2.5

235

220

≥ 2.5

220

Table 21. SnPb eutectic process (from J-STD-020D)

Package reflow temperature (°C)

Volume (mm³)

Package thickness (mm)

< 350

350 to 2000

> 2000

< 1.6

260

1.6 to 2.5

260

250

245

> 2.5

250

245

Table 22. Lead-free process (from J-STD-020D)

Moisture sensitivity precautions, as indicated on the packing, must be respected at all

times.

PCF8553

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 4 — 20 April 2021

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