Nxp Semiconductors LPC2919 User Manual

LPC2917_19_1

© NXP B.V. 2007. All rights reserved.

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:

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 

parallel to the transport direction of the printed-circuit board;

– smaller than 1.27 mm, the footprint longitudinal axis must be parallel to the 

transport direction of the printed-circuit board.

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.

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.

 

Through-hole mount

CPGA, HCPGA

suitable

−

−

DBS, DIP, HDIP, RDBS, SDIP, SIL

suitable

[3]

−

suitable

Through-hole-surface 
mount

PMFP

[4]

not suitable

not suitable

−