lpc2917 NXP Semiconductors, lpc2917 Datasheet - Page 59

• Manufacturer Part Number: lpc2917
• Description: Arm9 Microcontroller With Can And Lin
• Manufacturer: NXP Semiconductors

NXP Semiconductors
14. Soldering
LPC2917_19_1
Preliminary data sheet
14.2.1 Soldering by dipping or by solder wave
14.2.2 Manual soldering
14.3.1 Reflow soldering
14.1 Introduction
14.2 Through-hole mount packages
14.3 Surface mount packages
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.
Typical dwell time of the leads in the wave ranges from 3 seconds to 4 seconds at 250 qC
or 265 qC, depending on solder material applied, SnPb or Pb-free respectively.
The total contact time of successive solder waves must not exceed 5 seconds.
The device may be mounted up to the seating plane, but the temperature of the plastic
body must not exceed the specified maximum storage temperature (T
printed-circuit board has been pre-heated, forced cooling may be necessary immediately
after soldering to keep the temperature within the permissible limit.
Apply the soldering iron (24 V or less) to the lead(s) of the package, either below the
seating plane or not more than 2 mm above it. If the temperature of the soldering iron bit is
less than 300 qC it may remain in contact for up to 10 seconds. If the bit temperature is
between 300 qC and 400 qC, contact may be up to 5 seconds.
Key characteristics in reflow soldering are:
•
•
•
Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see
reducing the process window
Solder paste printing issues including smearing, release, and adjusting the process
window for a mix of large and small components on one board
Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature) and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joints (a solder paste
characteristic). In addition, the peak temperature must be low enough that the
packages and/or boards are not damaged. The peak temperature of the package
depends on package thickness and volume and is classified in accordance with
Table 32
and
33
Rev. 1.01 — 15 November 2007
Figure
ARM9 microcontroller with CAN and LIN
16) than a PbSn process, thus
LPC2917/19
stg(max)
© NXP B.V. 2007. All rights reserved.
). If the
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