USBULC1606-4M8

Recommendation on PCB assembly

Doc ID 16864 Rev 1

11/15

4

Recommendation on PCB assembly

4.1

Stencil opening design

1.

General recommendation on stencil opening design

a)

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

Figure 22.

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 23.

Recommended stencil window position

L

T

W

Aspect Ratio

W

T

-----

1.5

≥

=

Aspect Area

LW

×

2T L

W

+

()

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

0.66

≥

=

200 µm

190 µm

12.5 µm

12.5 µm

5µm

5µm

1200 µm

400

450 µm

µm

960 µm

120 µm

120 µm

80 µm

80 µm

Footprint

Stencil windo w

Footprint

0.4

0.2

0.45

0.225

1.4

1.75

0.4

1.2

Obsolete

Product(s)

- Obsolete

Product(s)