TS472

Application information

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5.3

Lower cut-off frequency

in an application because of DC voltage blocking.

Figure 33 and Figure 34 give directly the lower cut-off frequency (with 3dB attenuation)

versus the value of the input or output capacitors

Note:

filter on the input and the 1st order high-pass filter on the output create a 2nd order high-

40dB

5.4

Low-noise microphone bias source

The TS472 provides a very low noise voltage and power supply rejection BIAS source

designed for biasing an electret condenser microphone cartridge. The BIAS output is

drop-out, determined by the internal resistance 100

Ω (for detailed load regulation curves

see Figure 8).

C

in

1

2

π F

CL

100

3

× 10

⋅⋅

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

=

C

out

1

2

π F

CL

R

out

⋅⋅

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

=

Figure 33.

Lower cut-off frequency vs. input

capacitors

Figure 34.

Lower cut-off frequency vs. output

capacitors

1

10

100

10

100

1000

Typical Zin

ZinMAX

Cin (nF)

ZinMIN

1

10

100

1000

10

100

1000

Rout=10k

Ω

Cout (nF)

Rout=100k

Ω