pca9574 NXP Semiconductors, pca9574 Datasheet - Page 23

• Manufacturer Part Number: pca9574
• Description: 8-bit I2c-bus And Smbus, Level Translating, Low Voltage Gpio With Reset And Interrupt
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9574_1
Product data sheet
17.4 Reflow soldering
Key characteristics in reflow soldering are:
Table 16.
Table 17.
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
Package thickness (mm)
< 2.5
Package thickness (mm)
< 1.6
1.6 to 2.5
> 2.5
•
•
•
•
•
2.5
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
Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see
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 16
SnPb eutectic process (from J-STD-020C)
Lead-free process (from J-STD-020C)
and
Figure
17
21.
Rev. 01 — 15 May 2008
8-bit I
Package reflow temperature ( C)
Volume (mm
< 350
235
220
Package reflow temperature ( C)
Volume (mm
< 350
260
260
250
2
C-bus and SMBus, level translating, low voltage GPIO
3
3
)
)
Figure
350 to 2000
260
250
245
21) than a SnPb process, thus
220
220
350
> 2000
260
245
245
PCA9574
© NXP B.V. 2008. All rights reserved.
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