Application information

TS472

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5

Application information

5.1

Differential configuration principle

The TS472 is a full-differential input/output microphone preamplifier. The TS472 also

includes a common mode feedback loop that controls the output bias value to average it at

consequence, maximize the input dynamic voltage range.

The advantages of a full-differential amplifier are:

●

Very high PSRR (power supply rejection ratio).

●

High common mode noise rejection.

●

In theory, the filtering of the internal bias by an external bypass capacitor is not

necessary. But, to reach maximum performance in all tolerance situations, it is better to

keep this option.

5.2

Higher cut-off frequency

TS472 has an internal first order low pass filter (R=40k

Ω, C=100pF) to limit the highest cut-

Figure 32 below indicates directly the higher cut-off frequency in Hz versus the value of the

Figure 32.

Higher cut-off frequency vs. output

capacitors

F

CH

1

2

π 40

3

× 10

C

12

,

100

12

–

× 10

+

()

⋅⋅

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

=

200

400

600

800

1000

1

10

C1, C2 (pF)

40