
Koninklijke Philips Electronics N.V. Copyright 2001. All rights reserved.
9397 750 08865
80 of 84
Rev. 02 — 8 October 2001
Product data
PNX8510/11
Philips Semiconductors
Analog Companion Chip
14.
Soldering
14.1 Introduction to Soldering Surface-Mount Packages
The following information provides a very brief insight into a complex technology. A more in-
depth account of soldering ICs can be found in the Philips’ Data Handbook IC26; Integrated
Circuit Packages (document order number 9398 652 90011).
There is no soldering method that is ideal for all surface-mount IC packages. Wave soldering
can still be used for certain surface mount ICs, but it is not suitable for fine pitch SMDs. In these
situations reflow soldering is recommended.
For the PNX8510/11 only reflow soldering is suitable.
14.2 Reflow Soldering
Reflow soldering requires solder paste (a suspension of fine solder particles, flux and binding
agent) to be applied to the printed circuit board by screen printing, stencilling or pressure-syringe
dispensing before package placement.
Several methods exist for reflowing; for example, convection or convection/infrared heating in a
conveyor type oven. Throughput times (preheating, soldering and cooling) vary between
100 and 200 seconds depending on heating method.
Typical reflow peak temperatures range from 215 to 250
° C. The top-surface temperature of the
packages should preferably be kept below 220
° C for thick/large packages, and below 235° C for
small/thin packages.
14.3 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.
14.4 Footprint
For good thermal behavior of the PNX8510/11 in the application, the exposed pad needs to be
soldered to the motherboard.
Figure 29 shows the recommended footprint and solderpaste
placement. A matrix of solderpaste dots has to be placed on a copper square. For optimal heat
dissipation through the motherboard, the recommendation is to connect the copper square with
vias to the inner-ground plane of the application board.