PCF85263ATLSLASHA datasheet(79/92 Pages) NXP

79 / 92 page

NXP Semiconductors

PCF85263A

Tiny Real-Time Clock/calendar with alarm function, battery switch-over, time stamp input, and I2C-bus

20.3 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

20.4 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 51) 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 69 and Table 70

Package reflow temperature (°C)

Volume (mm³)

Package thickness (mm)

< 350

≥ 350

< 2.5

235

220

≥ 2.5

220

Table 69. 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 70. Lead-free process (from J-STD-020D)

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 51.

PCF85263A

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

Product data sheet

Rev. 5 — 1 February 2021

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PCF85263ATL/A Datasheet(PDF) 79 Page - NXP Semiconductors

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