Application Information

TS472

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Application Information

4.1

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 Vcc/2. This

allows the device to always have a maximum output voltage swing, and by 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 performances in all tolerance situations, it’s better to keep this

option.

4.2

Higher cut-off frequency

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

Ω, C=100pF) to limit the highest cut-off

regard to following formula:

Figure 30. 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