NXP Semiconductors LPC2919 user manual Manual soldering, DLPC2917/19

NXP Semiconductors

DRAFT	D	D		AFT
	RAFT	RAFT AFT
			DR	DR

DLPC2917/19

ARM9 microcontrollerRAFT withDRAFTCANDRAFTand LINDRAFT

	T	DRAFT	T
	DRA		DRA		DR
developed.	F		F
	DRAFT DRAFT			DRAF
To overcome these problems the double-wave soldering method was specifically
		DRAFT DRAFT
If wave soldering is used the following conditions must be observed for optimal results:
			DRAFT		D
• Use a double-wave soldering method comprising a turbulent wave with high upward
pressure followed by a smooth laminar wave.					DRA
• 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.

14.3.3Manual soldering

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.

14.4Package related soldering information

Table 34. Suitability of IC packages for wave, reflow and dipping soldering methods

Mounting

Package[1]

Soldering method

Wave Reflow[2] Dipping

Through-hole mount	CPGA, HCPGA	suitable	−	−
	DBS, DIP, HDIP, RDBS, SDIP, SIL	suitable[3]	−	suitable
Through-hole-surface	PMFP[4]	not suitable	not suitable	−
mount

LPC2917_19_1 © NXP B.V. 2007. All rights reserved.

Preliminary data sheet Rev. 1.01 — 15 November 2007 61 of 68