INMP421

PCB DESIGN AND LAND PATTERN LAYOUT

Lay out the PCB land pattern for the INMP421 at a 1:1 ratio to the solder pads on the microphone package (see Figure 13.) Take care

to avoid applying solder paste to the sound hole in the PCB. Figure 14 shows a suggested solder paste stencil pattern layout.

The response of the INMP421 is not affected by the PCB hole size, as long as the hole is not smaller than the sound port of the micro-

phone (0.25 mm, or 0.010 inch, in diameter). A 0.5 mm to 1 mm (0.020 inch to 0.040 inch) diameter for the hole is recommended.

Align the hole in the microphone package with the hole in the PCB. The exact degree of the alignment does not affect the

performance of the microphone as long as the holes are not partially or completely blocked.

Figure 13. Suggested PCB Land Pattern Layout

Dimensions shown in millimeters

Figure 14. Suggested Solder Paste Stencil Pattern Layout

Dimensions shown in millimeters

0.40 × 0.60 (4×)

(0.30)

0.90

(0.30)

ø1.70

3.80

(0.30)

0.35

2.80

2× R0.10

(0.30)

0.35

2.05

0.70

ø1.10

(1.000)

(0.550)

CENTER LINE

1.45

0.9

2.45

0.7

1.525

1.000

0.35

1.849

1.849

1.498

0.205 WIDE

0.248 × 0.498 (2×)

0.248 × 1.148 (2×)

0.248 × 0.948 (2×)

1.498 × 0.248

0.398 × 0.298 (4×)

0.362 CUT (3×)

1.17

24°

24°

0.375

CENTER

LINE

Page 16 of 21

Document Number: DS-INMP421-00

Revision: 1.0.