Practical information

STA540

20/23

6.9

PCB ground layout

The device has two distinct ground pins, P-GND (power ground) and S-GND (signal ground)

which are disconnected from each other at chip level. For superior performance the pins

P-GND and S-GND must be connected together on the PCB by low-resistance tracks.

For the PCB-ground configuration, a star-like arrangement, where the center is represented

by the supply-filtering electrolytic capacitor ground, is recommended. In an arrangement

such as this, at least two separate paths must be provided, one for P-GND and one for

S-GND.

The correct ground assignments are as follows:

"

on S-GND:

–

standby capacitor (pin 7, or any other standby driving networks),

–

SVR capacitor (pin 6), to be placed as close as possible to the device,

–

input signal ground (from active/passive signal processor stages)

"

on P-GND:

–

power supply filtering capacitors for pins 3 and 13. The negative terminal of the

electrolytic capacitor(s) must be directly tied to the battery negative line and this

should represent the starting point for all the ground paths.

6.10

Mute function

If the mute function is desired, it can be implemented on pin 6, SVR, as shown in Figure 29.

Figure 29.

Optional mute function circuit

Using a different value for R1 than the suggested 3.3 k

Ω, results in two different situations:

"

R1 > 3.3 k

Ω:

–

pop noise improvement,

–

lower mute attenuation;

"

R1 < 3.3 k

Ω:

–

pop noise degradation,

–

higher mute attenuation.

0.22

µF

1

DIAGNOSTICS

4

7

D06AU1632

10

µF

10K

ST-BY

IN L

0.47

µF

5

IN BRIDGE

12

470

µF

6

13

1000

µF

100nF

3

VS

2

15

14

OUT L

8

9

10

OUT

BRIDGE

11

0.22

µF

IN R

OUT R

2200

µF

2200

µF

R1 3.3K

R2 10K

MUTE

5V

0

PLAY