Philips TDA8944J 14. Application information

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.
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OUT1−
−
−
−
+
+
+
+
−
RL
8 Ω
Ri
45 kΩ
Rs
Symmetrical
input
Ri
45 kΩ
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
152
+VCC
1000 µF
100 nF
20 kΩ
20 kΩ
10
µF
−
−
−
+
+
+
+
−
Ri
45 kΩ
Ri
45 kΩ
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