Philips Semiconductors

TDA8944J

2 x 7 W stereo BTL audio amplifier

Product specification

Rev. 02 — 14 February 2000

13 of 21

9397 750 06861

© Philips Electronics N.V. 2000. All rights reserved.

14. Application information

14.1 Printed-circuit board (PCB)

14.1.1

Layout and grounding

For a high system performance level certain grounding techniques are essential.

The input reference grounds have to be tied with their respective source grounds and

must have separate tracks from the power ground tracks; this will prevent the large

(output) signal currents from interfering with the small AC input signals.

The small-signal ground tracks should be physically located as far as possible from

the power ground tracks. Supply and output tracks should be as wide as possible for

delivering maximum output power.

Fig 14. Application diagram.

3

16

OUT1

−

−

−

−

+

+

+

+

−

RL

8

Ω

Ri

45 k

Ω

Rs

Symmetrical

input

Ri

45 k

Ω

RL

8

Ω

OUT1

+

IN1

−

IN1

+

OUT2

−

OUT2

+

GND

MGL950

IN2

−

IN2

+

MODE

SVR

1

8

220 nF

6

9

12

10

11

4

14

17

15

2

+VCC

1000

µF

100 nF

20 k

Ω

20 k

Ω

10

µF

−

−

−

+

+

+

+

−

Ri

45 k

Ω

Ri

45 k

Ω

R

C1

C2

R

VCC

VCC

signal

GND

TDA8944J

signal

GND

SHORT CIRCUIT

AND

TEMPERATURE

PROTECTION

STANDBY/

MUTE LOGIC

MICROCONTROLLER

Standby

MODE

Mute

On

0

0

1

0

C1

C2

1

0

1/2 VCC

220 nF

1.5

nF

1.5

nF

Ci

Rs

Asymmetrical

input

220 nF

220 nF

Ci

1/2 VCC

1/2 VCC

1/2 VCC

1/2 VCC