TDA7266 Datasheet, PDF (4/7 Pages) STMicroelectronics – 7+7W DUAL BRIDGE AMPLIFIER

TDA7266
APPLICATION SUGGESTION
LINEAR INTEGRATED CIRCUIT
For Microprocessor Application
In order to avoid annoying ”Pop-Noise” during Turn-On/Off transients, it is necessary to guarantee the right ST-BY
and MUTE signals sequence. It is quite simple to obtain this function using a microprocessor (Fig 1 and Fig 2).
At first ST-BY signal (from mP) goes high and the voltage across the ST-BY terminal (Pin 7) starts to increase
exponentially. The external RC network is intended to turn-on slowly the biasing circuits of the amplifier, this to
avoid ”POP” and ”CLICK” on the outputs.
When this voltage reaches the ST-BY threshold level, the amplifier is switched-on and the external capacitors in
series to the input terminals (C3, C5) start to charge.
It’s necessary to maintain the mute signal low until the capacitors are fully charged, this to avoid that the device
goes in play mode causing a loud “Pop Noise” on the speakers.
A delay of 100 ~ 200ms between ST-BY and MUTE signals is suitable for a proper operation.
IN1
ST-BY
C1
0.22µF
R1
10k
4
7
C2
10µF
Vcc
3 13
C5
470µF
1 OUT1+
C6
100nF
S-GND ₉
µP
C3
2 OUT1-
0.22µF
IN2
TDA7266
12
15 OUT2+
MUTE
6
R2 C4
10k 1µF
PW-GND ₈
14 OUT2-




Fig. 1 Microprocessor Application

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www.unisonic.com.tw
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QW-R107-037,A