Recommendation on PCB assembly

SPT01-335DEE

12/16

DocID15200 Rev3

7

Recommendation on PCB assembly

7.1

Stencil opening design

1.

General recommendation on stencil opening design

a)

Stencil opening dimensions: L (Length), W (Width), T (Thickness).

Figure 15. Stencil opening dimensions

b)

General design rule

Stencil thickness (T) = 75 ~ 125 µm

2.

Reference design

a)

Stencil opening thickness: 100 µm

b)

Stencil opening for central exposed pad: Opening to footprint ratio is 50%.

c)

Stencil opening for leads: Opening to footprint ratio is 90%.

Figure 16. Recommended stencil window position

L

T

W

Aspect Ratio

W

T

-----

1,5

≥

=

Aspect Area

LW

×

2T L

W

+

()

----------------------------

0,66

≥

=

0.3

0.354

0.329

0.014

0.011

0.379

0.95

1.70

1.202

0.5

0.073

0.044

0.4

0.32

0.53

0.20

0.032

2.249

0.141

0.503