lpc2939fbd208 NXP Semiconductors, lpc2939fbd208 Datasheet - Page 91

• Manufacturer Part Number: lpc2939fbd208
• Description: Arm9 Microcontroller With Can, Lin, And Usb
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC2939_1
Preliminary data sheet
12.4 Reflow soldering
Key characteristics in reflow soldering are:
Table 44.
Table 45.
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see
Package thickness (mm)
< 2.5
Package thickness (mm)
< 1.6
1.6 to 2.5
> 2.5
•
•
•
2.5
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 44
SnPb eutectic process (from J-STD-020C)
Lead-free process (from J-STD-020C)
and
Figure
45
41.
Rev. 01 — 11 June 2009
Package reflow temperature ( C)
Volume (mm
< 350
235
220
Package reflow temperature ( C)
Volume (mm
< 350
260
260
250
3
3
ARM9 microcontroller with CAN, LIN, and USB
)
)
Figure
350 to 2000
260
250
245
41) than a SnPb process, thus
220
220
350
> 2000
260
245
245
LPC2939
© NXP B.V. 2009. All rights reserved.
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