LA4815VH

No.A1374-7/15

3. Mute control pin (Pin 3)

The internal power amplifier circuit can be disabled and audio mute is turned on by controlling the voltage applied to

Pin 3. Control can be performed directly using the CPU output port, but digital noise from the CPU may worsen the

LA4815VH noise floor. Therefore, inserting a series resistor, Rm1 (1 to 2.2k

Ω) as shown in Fig. 6, is recommended.

• Mute ON : Low

• Mute OFF : High or open

In addition, the Pin 3 DC voltage is dependent on the supply voltage, so a reverse current flows to the CPU power

supply line when the Pin 3 voltage is higher than the CPU supply voltage. In these cases, connect a resistor, Rm2 (see

Fig. 7) between Pin 3 and GND to lower the Pin 3 DC voltage as shown in Fig. 6.

Note that when not using the mute function, Pin 3 must be left open.

Figure 6

Reverse current prevention resistor value : Rm2 (reference value)

← When V3 is set to approximately 2.5V

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 2 and 3 can also rise simultaneously.

During power-off : Twd = 100 to 200ms

Figure 8

Pin 2

(VCC)

Pin 3

(MUTE)

Twd

Twu

Rm2 – VCC

10

100

7

5

3

2

7

5

3

2

1000

610

12

14

16

18

820

Supply voltage, VCC –V

Rm1

Rm2

VDD

VSS

CPU

LA4815VH

GND

VCC

3

* For reverse

current prevention