Description of the demonstration board

AN2240

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Doc ID 11677 Rev 4

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Description of the demonstration board

The STEVAL-CCA023V1 is a demonstration board designed for the TS472 low noise

microphone preamplifier with 2.0 V bias and active-low standby mode.

This demonstration board helps you to customize the conditions in which you conduct

evaluation testing. Specifically, you can:

●

set the adjustable gain of the TS472 device,

●

use the TS472 built-in 2.0 V bias voltage to bias an electret microphone,

●

or, externally bias the electret microphone.

1.1

Setting the adjustable gain

The gain of the TS472 is set by using the P5 connectors.

The connector has 7 jumper positions. By modifying the jumper positions, you can select

any of the following gain values:

●

-1.5 dB (minimum possible gain)

●

0dB

●

10 dB

●

20 dB

●

30 dB

●

40 dB

●

41 dB (maximum possible gain)

Refer to Table 1: Demonstration board connector description to see how to place the jumper

to obtain the desired gain value.

1.2

Output bias options

On the board, the R6, R7, R11 component locations are left empty to allow you to evaluate

the TS472 in a typical application with an electret microphone biased by the TS472’s built-in

2.0 V low noise bias output. To use the TS472’s built-in biasing, the P6 connector must be

closed and P7 must be left floating (refer to Table 1: Demonstration board connector

description).

Alternatively, you can use the R10 empty component locations to externally bias the electret

microphone. To do this:

1.

connect the external bias voltage using the P7 connector.

2.

leave the P6 connector open.

3.

assemble the missing components.