TS4999 datasheet(25/36 Pages) STMICROELECTRONICS

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TS4999

Application information

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In some cases, the speaker volume can increase when the 3D effect is switched on. This

factor is dependent on the composition and frequency spectrum of listened stereo audio

signal.

Note:

When the 3D effect is switched on, both channels must be in operation or shutdown mode at

the same time.

Between pin 3D and GND there is an internal 300 k

Ω (+/-20%) resistor. When the pin is

floating, the 3D effect is off. In full standby (left and right channels OFF), this resistor is

disconnected (HiZ input).

4.4

Low frequency response

If a low frequency bandwidth limitation is required, input coupling capacitors can be used. In

the low frequency region, the input coupling capacitor Cin starts to have an effect. Cin forms,

with the input impedance Zin, a first order high-pass filter with a -3 dB cut-off frequency.

So, for a desired cut-off frequency FCL, Cin is calculated as follows:

with FCL in Hz, Zin in Ω and Cin in F.

The input impedance Zin is for the whole power supply voltage range and changes with the

gain setting. There is also a tolerance around the typical values (see Table 8, Table 9 and

Table 10.

Figure 56.

Cut-off frequency vs. input capacitor

π Z

⋅⋅

⋅

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

π Z

⋅⋅

⋅

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

0.1

100

G=3.5dB, 6dB, 9.5dB

3D on, Zin=17.1k

Ω typ.

G=3.5dB, 6dB, 9.5dB

3D off, Zin=30k

Ω typ.

G=12dB, 3D on

Zin=8.6k

Ω typ.

G=12dB, 3D off

Zin=15k

Ω typ.

Tamb=25

°C

Input Capacitor Cin (

μF)

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