TDA7266M Datasheet, PDF (3/9 Pages) STMicroelectronics – 7W MONO BRIDGE AMPLIFIER

ELECTRICAL CHARACTERISTICS (Continued)
Symbol
VTST-BY
I_ST-BY
e_N
Parameter
St-by Threshold
ST-BY current V6 = GND
Total Output Noise Voltage
Test Condition
A curve
f = 20Hz to 20kHz
TDA7266M
Min.
0.8
Typ.
1.3
150
Max.
1.8
100
Unit
V
µA
µV
APPLICATION SUGGESTION
STAND-BY AND MUTE FUNCTIONS
(A) Microprocessor Application
In order to avoid annoying ”Pop-Noise” during
Turn-On/Off transients, it is necessary to guaran-
tee the right St-by and mute signals sequence.
It is quite simple to obtain this function using a mi-
croprocessor (Fig. 1 and 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
Figure 1: Microprocessor Application
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 mantain 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.
C1 0.22µF
4
IN1
ST-BY R1 10K
7
C2
10µF
µP
S-GND
9
Vref
MUTE ^{R2 10K}
6
C4
1µF
VCC
3
13
C5
470µF
+
1 OUT1+
-
C6
100nF
-
2 OUT1-
+
PW-GND
8
D98AU833A
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