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GTL2008 Datasheet, PDF (16/20 Pages) NXP Semiconductors – 12-bit GTL to LVTTL translator with power good control and high-impedance LVTTL and GTL outputs | |||
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Philips Semiconductors
GTL2008; GTL2107
GTL translator with power good control and high-impedance outputs
15. Soldering
15.1 Introduction to soldering 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 ï¬ne pitch
SMDs. In these situations reï¬ow soldering is recommended.
15.2 Reï¬ow soldering
Reï¬ow soldering requires solder paste (a suspension of ï¬ne solder particles, ï¬ux and
binding agent) to be applied to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement. Driven by legislation and
environmental forces the worldwide use of lead-free solder pastes is increasing.
Several methods exist for reï¬owing; for example, convection or convection/infrared
heating in a conveyor type oven. Throughput times (preheating, soldering and cooling)
vary between 100 seconds and 200 seconds depending on heating method.
Typical reï¬ow temperatures range from 215 °C to 260 °C depending on solder paste
material. The peak top-surface temperature of the packages should be kept below:
Table 14. SnPb eutectic process - package peak reï¬ow temperatures (from J-STD-020C
July 2004)
Package thickness
Volume mm3 < 350
Volume mm3 ⥠350
< 2.5 mm
240 °C + 0/â5 °C
225 °C + 0/â5 °C
⥠2.5 mm
225 °C + 0/â5 °C
225 °C + 0/â5 °C
Table 15. Pb-free process - package peak reï¬ow temperatures (from J-STD-020C July
2004)
Package thickness
Volume mm3 < 350
Volume mm3 350 to Volume mm3 > 2000
2 000
< 1.6 mm
260 °C + 0 °C
260 °C + 0 °C
260 °C + 0 °C
1.6 mm to 2.5 mm
260 °C + 0 °C
250 °C + 0 °C
245 °C + 0 °C
⥠2.5 mm
250 °C + 0 °C
245 °C + 0 °C
245 °C + 0 °C
Moisture sensitivity precautions, as indicated on packing, must be respected at all times.
15.3 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 speciï¬cally
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):
GTL2008_GTL2107_2
Product data sheet
Rev. 02 â 26 September 2006
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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