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Home Knowledge Centre Pad Reduction Criteria for laser cut stencil

Knowledge Centre

Pad Reduction Criteria for laser cut stencil
Leaded Assembly

CHIP

0402 Package:

0603 Package:

Lager than 0805:

Big CHIP: Reduction 10% of the pad area
Diode: No Reduction. Please keep pad size 1:1

 

Crystal

SOT23:No Reduction. Please keep pad size 1:1
SOT89:

SOT143: No Reduction. Please keep pad size 1:1

SOT252, SOT223:

IC (In the same stencil, W needs to be kept same)

  • PITCH=0.8-1.27mm, W=45%-60%, L=1:1
  • PITCH=0.635-0.65mm, W=0.32mm, L=1:1
  • PITCH=0.5mm, W=0.24mm,L=1:1 and circle the corner
  • PITCH=0.4mm, W=0.19mm, L needs to be extended 0.1mm outside,
      enlarge (L) size 0.05mm and then circle the corner
  • PITCH=0.3mm, W=0.16mm, L needs to be extended 0.1mm outside

Big pad L >= 4mm and W >= 3mm – pad reduction as follow:

Lead-FREE (RoHS) Assembly

CHIP

0402 Package: Enlarge pad area 10% and then do following

0603 Package: Enlarge pad area 5% and then do following

Lager than 0805: Enlarge pad area 10%

IC (In the same stencil, W needs to be kept same)

  • PITCH=0.8-1.27mm, W=50%-60% L enlarge 5%
  • PITCH=0.635-0.65mm, W=0.32mm, L enlarge 5%
  • PITCH=0.5mm, W=0.24mm,L enlarge 5% and then circle the corner
  • PITCH=0.4mm, W=0.19mm,L needs to be extended 0.1mm outside,
      enlarge (L) 5% and then circle the corner
  • PITCH=0.3mm, W=0.16MM,L move out 0.1mm,
      L enlarge 5% and circle the corner
PCB Design Tips

PCB Design Tips

When designing a PCB, try to limit the amount of draws you use. Draws use a lot of memory and slow the programming time. Use a flash for pads instead.

More tips

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