Preliminary Technical Data

ADMP404

Rev. PrH | Page 7 of 12

APPLICATIONS INFORMATION

The ADMP404 output can be connected to a dedicated codec

microphone input (see Figure 7) or to a high input impedance

placed close to the ADMP404 supply pins is used for testing and

is recommended to adequately decouple the microphone from

noise on the power supply. A 1 µF or larger dc-blocking tantalum

capacitor (C2) is required at the output of the microphone.

CONNECTING THE ADMP404 TO A CODEC

ADAU1761

ADMP404

MIC INPUT

C2

1µF

C1

0.1µF

GND

GND

GND

OUTPUT

Figure 7. ADMP404 Connected to the Analog Devices ADAU1761 Codec

CONNECTING THE ADMP404 TO AN OP AMP GAIN

STAGE

ADMP404

R1

10k

Ω

R3

R2

GND

GND

OUTPUT

3

2

4

7

6

GND

U1

OP177

GAIN = (R2 + R3)/R3

C2

1µF

C1

0.1µF

Figure 8. ADMP404 Connected to the OP177 Op Amp