SC7422 Ver la hoja de datos (PDF) - Silan Microelectronics
Número de pieza
componentes Descripción
Fabricante
SC7422 Datasheet PDF : 8 Pages
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SC7422
(Continued)
Step
Volume
(dB)
6
-7.5
7
-9
8
-10.5
9
-12
10
-13.5
11
-15
12
-16.5
13
-18
14
-19.5
15
-21
16
-22.5
DC Vol
VH(%)
57.9
56.1
54.1
52.1
49.4
47.5
45.5
44.0
41.8
39.8
38.3
DC Vol
VL(%)
56.0
54.0
51.8
48.8
47.4
45.4
43.6
41.6
39.8
37.6
36.6
Step
22
23
24
25
26
27
28
29
30
31
32
Volume
(dB)
31.5
-33
-34.5
-36
-37.5
-39
-40.5
-42
-43.5
-45
MUTE
DC Vol
VH(%)
26.2
24.0
22.5
20.4
18.0
15.1
13.1
10.6
8.8
6.7
4.3
DC Vol
VL(%)
21.8
20.0
18.0
14.4
13.0
11.0
9.0
7.2
5.4
3.0
GND
Output Mode Control
The output mode of the SC7422 can be switched between the SE (Single-Ended) and BTL (Bridge-Tied Load)
mode. It is recommended to apply BTL mode to obtain more output power while driving the loud speaker. SE
mode can be set to shutdown some parts of amplifiers while driving the stereo headphone. Therefore, the
quiescent operation current is reduced.
POPO Noise Suppress
When an audio power amplifier with a single supply turns on, the POPO Noise can be heard. The reason is that
the output voltage of amplifier would take hundreds of milliseconds to increase from 0V to 1/2 Vcc.
This time is controlled by CB, the external capacitor of Bypass pin. As the CB was increasing, the time is longer,
so it is much better to suppress POPO noise. However, the charging and discharging time for the input or output
capacitors should be less than this time. Therefore, CB is related with the input or output capacitors. The values
of these capacitors are recommended in the typical application circuit.
Thermally protected
There is a thermally protected protection circuit in the SC7422. If the chip temperature is over 120°C, the
protection circuit will start up to shutdown the output stages of audio power amplifier. The chip will return to the
normal operation, until the chip temperature falls to 80°C.
Power Dissipation and Heat Sinking
When the load is a resistor, the maximum of average power dissipation for the SC7422 is calculated as follows:
PDISS(MAX) = 2(2Vcc)2 / (2π2RL) + PQ
Where Vcc is the operation voltage, RL is the load resistor, PQ is the static power consumption.
PQ=VCC×Is
Where Is is the operation current. For example, if the SC7422 drives the 4¡ load in 5V supply, the power
dissipation is 2.6W.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: www.silan.com.cn
REV:1.0 2006.11.13
Page 5 of 8
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