3

DS1126DB1

CDB7121P

1 System Overview

1 System Overview

The CDB7121P customer demo board is a flexible PCB for evaluating the WM7121P low-profile analog silicon

microphone. The following subsections describe the features of CDB7121P customer demo board in detail.

1.1 Test Points

Six test points are available to provide all the connections from WM7121P to standard test equipment for full acoustic

measurement. Test points are described in Table 1-1. The operating supply voltage of WM7121P is provided in the data

sheet, which is available from Cirrus website.

1.2 Edge Connector

The J1 and J2 edge connector pads provide a pluggable connection to a codec main board with compatible edge card

socket. The edge connector pin-outs are described in Table 1-2 and Table 1-3.

1.3 Trim Line

To enable more accurate free field frequency responses to be obtained, the flexible region of the CDB7121P may be

trimmed to reduce acoustic interactions. If required, there is a guide line on the silkscreen that can be cut along. Refer to

Fig. 4-1 for further details.

Table 1-1. Test Point signals

Test Point

Pin

Direction

Description

TP1

VDD

Supply

Analog Supply

TP2

OP+

Output

Microphone analogue output signal

TP3

NA

NA

Not Applicable

TP4, TP5, TP6

GND

Ground reference

Analog Ground

Table 1-2. Edge connection J1

Pin

Pin

Direction

Description

1

OP+

Output

Microphone analogue output signal

(pin 1 is marked by a small dot)

2

VDD

Supply

Analog supply from codec MICBIAS

3, 7

GND

Ground reference

Analog ground

8

—

—

Not applicable

4, 5, 6, 9, 10

NC

—

No connection

Table 1-3. Edge connection J2

Pin

Pin

Direction

Description

1,2,3,4,5,6,7,8,9,10

NC

NA

No Connection