Recommendation on PCB assembly

HSP061-2

8/12

Doc ID 022777 Rev 1

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 17.

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 leads: Opening to footprint ratio is 90%.

Figure 18.

Recommended stencil window position for µQFN-6L

L

T

W

Aspect Ratio

W

T

-----

1.5

≥

=

Aspect Area

LW

×

2T L

W

+

()

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

0.66

≥

=

250 µm

236 µm

15 µm

15 µm

7µm

7µm

Footprint

Stencil window

Footprint