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SA56004X Datasheet, PDF (31/36 Pages) NXP Semiconductors – 1 Degrees Celcious accurate, SMBus-compatible, 8-pin, remote/local digital temperature sensor with over temperature alarms | |||
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NXP Semiconductors
SA56004X
Digital temperature sensor with overtemperature alarms
Not all SMDs can be wave soldered. Packages with solder balls, and some leadless
packages which have solder lands underneath the body, cannot be wave soldered. Also,
leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered,
due to an increased probability of bridging.
The reï¬ow soldering process involves applying solder paste to a board, followed by
component placement and exposure to a temperature proï¬le. Leaded packages,
packages with solder balls, and leadless packages are all reï¬ow solderable.
Key characteristics in both wave and reï¬ow soldering are:
⢠Board speciï¬cations, including the board ï¬nish, solder masks and vias
⢠Package footprints, including solder thieves and orientation
⢠The moisture sensitivity level of the packages
⢠Package placement
⢠Inspection and repair
⢠Lead-free soldering versus SnPb soldering
14.3 Wave soldering
Key characteristics in wave soldering are:
⢠Process issues, such as application of adhesive and ï¬ux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are
exposed to the wave
⢠Solder bath speciï¬cations, including temperature and impurities
14.4 Reï¬ow soldering
Key characteristics in reï¬ow soldering are:
⢠Lead-free versus SnPb soldering; note that a lead-free reï¬ow process usually leads to
higher minimum peak temperatures (see Figure 24) than a SnPb process, thus
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
⢠Reï¬ow temperature proï¬le; this proï¬le includes preheat, reï¬ow (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 classiï¬ed in accordance with
Table 20 and 21
Table 20. SnPb eutectic process (from J-STD-020C)
Package thickness (mm) Package reï¬ow temperature (°C)
Volume (mm3)
< 350
⥠350
< 2.5
235
220
⥠2.5
220
220
SA56004X_5
Product data sheet
Rev. 05 â 22 May 2008
© NXP B.V. 2008. All rights reserved.
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