TDA7437N datasheet(24/34 Pages) STMICROELECTRONICS

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Mute and pause features

TDA7437N

24/34

When the incoming signal is detected to be outside the selected window, the external

capacitor is discharged. When the signal is inside the window, the capacitor is integrating up

(see Figure 15 and Figure 16).

by reading directly the Pause pin level.The ON/OFF voltage threshold is 3.0V

typical. Pause OFF = level low (< 3.0V) Pause ON = level high ( ; 3.0V)

by reading via I2C bus the transmitted byte, bit PP = 0 pause active. P = 1 no

pause detected. The external capacitor value fixes the time constant.

The pull up current is 25uV typical, with input signal

Vin = 1Vrm --; Vdc pin pause = 15mV

Vin = 0Vrms --; Vdc pin pause = 5.62V

For example choosing Cpause = 100nF the charge up constant is about 22ms. Instead with

Cpause = 15nF the charge up constant is about 360

μs.

The pause detection is useful in applications like RDS, to perform noiseless tuning

frequency jumps, avoiding the use of the mute.

5.6

No symmetrical bass cut response

bit D7 = 0 No symmetrical

bit D7 = 1 Symmetrical

The bass stage has the option to generate an unsymmetrical response, for cut mode

settings (bass level from -2db to - 14dB)

For example using a T-type band pass external

The feature is useful for human ear equalization in a noisy environment, like a car.

See examples in Figure 17 (symmetrical response) and Figure 18 (unsymmetrical

response).

5.7

Transmitted data (send mode)

bitP = 0Pause active

bitP = 1No pause detected

bitZM = 1Zero cross mute ON

bitZM = 0Zero cross mute OFF

bitSM = 1Soft mute ON

bitSM = 0Soft mute OFF

bitST = 1Stereo signal detected (input MPX)

bitST = 0Mono signal detected (input MPX)

The TDA7437N allows the reading of four info bits.

TDA7437N датащи(PDF) 24 Page - STMicroelectronics