P89LPC901FD datasheet(51/55 Pages) PHILIPS

51 / 55 page

Philips Semiconductors

P89LPC901/902/903

8-bit microcontrollers with two-clock 80C51 core

Product data

Rev. 04 — 21 November 2003

51 of 55

9397 750 12293

– for packages with a thickness

≥ 2.5 mm

– for packages with a thickness < 2.5 mm and a volume

≥ 350 mm3 so called

thick/large packages.

• below 240

°C (SnPb process) or below 260 °C (Pb-free process) for packages with

a thickness < 2.5 mm and a volume < 350 mm3 so called small/thin packages.

Moisture sensitivity precautions, as indicated on packing, must be respected at all

times.

14.3.2

Wave soldering

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:

• 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 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.

14.3.3

Manual 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 to 5 seconds between 270 and 320

°C.

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