pca8574 NXP Semiconductors, pca8574 Datasheet - Page 23

• Manufacturer Part Number: pca8574
• Description: Pca8574/pca8574a Remote 8-bit I/o Expander For I2c-bus With Interrupt
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Table 11.
PCA8574_PCA8574A_2
Product data sheet
Mounting
Through-hole mount
Through-hole-surface
mount
Suitability of IC packages for wave, reflow and dipping soldering methods
16.3.2 Wave soldering
16.3.3 Manual soldering
16.4 Package related soldering information
Conventional single wave soldering is not recommended for surface mount devices
(SMDs) or printed-circuit boards with a high component density, as solder bridging and
non-wetting can present major problems.
To overcome these problems the double-wave soldering method was specifically
developed.
If wave soldering is used the following conditions must be observed for optimal results:
During placement and before soldering, the package must be fixed with a droplet of
adhesive. The adhesive can be applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the adhesive is cured.
Typical dwell time of the leads in the wave ranges from 3 seconds to 4 seconds at 250 C
or 265 C, depending on solder material applied, SnPb or Pb-free respectively.
A mildly-activated flux will eliminate the need for removal of corrosive residues in most
applications.
Fix the component by first soldering two diagonally-opposite end leads. Use a low voltage
(24 V or less) soldering iron applied to the flat part of the lead. Contact time must be
limited to 10 seconds at up to 300 C.
When using a dedicated tool, all other leads can be soldered in one operation within
2 seconds to 5 seconds between 270 C and 320 C.
Package
CPGA, HCPGA
DBS, DIP, HDIP, RDBS, SDIP, SIL
PMFP
•
•
•
Use a double-wave soldering method comprising a turbulent wave with high upward
pressure followed by a smooth laminar wave.
For packages with leads on two sides and a pitch (e):
– larger than or equal to 1.27 mm, the footprint longitudinal axis is preferred to be
– smaller than 1.27 mm, the footprint longitudinal axis must be parallel to the
The footprint must incorporate solder thieves at the downstream end.
For packages with leads on four sides, the footprint must be placed at a 45 angle to
the transport direction of the printed-circuit board. The footprint must incorporate
solder thieves downstream and at the side corners.
[4]
parallel to the transport direction of the printed-circuit board;
transport direction of the printed-circuit board.
[1]
Rev. 02 — 14 May 2007
Soldering method
Wave
suitable
suitable
not suitable
Remote 8-bit I/O expander for I
[3]
PCA8574/74A
Reflow
not suitable
2
C-bus with interrupt
[2]
© NXP B.V. 2007. All rights reserved.
Dipping
suitable
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