LA4815M_10 Datasheet, PDF (7/14 Pages) Sanyo Semicon Device – Monaural Power Amplifier

LA4815M
3. Mute control pin (Pin 7)
The internal power amplifier circuit can be disabled and audio mute is turned on by controlling the voltage applied to
Pin 7. Control can be performed directly using the CPU output port, but digital noise from the CPU may worsen the
LA4815M noise floor. Therefore, inserting a series resistor, Rm1 (1 to 2.2kΩ) as shown in Fig. 6, is recommended.
• Mute ON : Low
• Mute OFF : High or open
In addition, the Pin 7 DC voltage is dependent on the supply voltage, so a reverse current flows to the CPU power
supply line when the Pin 7 voltage is higher than the CPU supply voltage. In these cases, connect a resistor, Rm2 (see
Fig. 7) between Pin 7 and GND to lower the Pin 7 DC voltage as shown in Fig. 6.
Note that when not using the mute function, Pin 7 must be left open.
LA4815M
VDD
VCC
VSS
CPU
1kΩ
Rm1
7
Rm2
* For reverse
current prevention
10kΩ
30kΩ
40kΩ
30kΩ
GND
Figure 6
Reverse current prevention resistor value : Rm2 (reference value) ← When V7 is set to approximately 2.5V
Rm2 – VCC
1000
7
5
3
2
100
7
5
3
2
10
7
9
11
13
15
Supply voltage, VCC – V
Figure 7
4. Mute control timing
When performing mute control, exercise control at the timing shown in Fig. 8.
During power-on : Twu = 0 to 50ms
* Pins 6 and 7 can also rise simultaneously.
During power-off : Twd = 100 to 200ms
Pin 6
(VCC)
Pin 7
(MUTE)
Twu
Twd
Figure 8
No.A1373-7/14