TDA8948J_1
© NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 01 — 27 February 2008
17 of 26
NXP Semiconductors
TDA8948J
4-channel audio amplifier
13.2 Printed-circuit board
13.2.1 Layout and grounding
To obtain a high-level system performance, 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.
13.2.2 Power supply decoupling
Proper supply bypassing is critical for low-noise performance and high supply voltage
ripple rejection. The respective capacitor location should be as close as possible to the
device and grounded to the power ground. Proper power supply decoupling also prevents
oscillations.
For suppressing higher frequency transients (spikes) on the supply line a capacitor with
low Equivalent Series Resistance (ESR), typical 100 nF, has to be placed as close as
possible to the device. For suppressing lower frequency noise and ripple signals, a large
electrolytic capacitor, e.g. 1000
µ
F or greater, must be placed close to the device.
The bypass capacitor on pin SVR reduces the noise and ripple on the mid rail voltage. For
good Total Harmonic Distortion (THD) and noise performance a low ESR capacitor is
recommended.
Fig 13. Printed-circuit board layout (single-sided); components view
mce483
AUDIO POWER CS NIJMEGEN
4.7 nF
220 nF
220 nF
220 nF
220 nF
220 nF
100 nF
27 Jan.
2003 / FP
220 nF
4
Ω
4
Ω
4
Ω
4
Ω
4
Ω
4
Ω
10 k
Ω
10 k
Ω
1000
µ
F
1000
µ
F
1000
µ
F
1000
µ
F
150
µ
F
22
µ
F
220
µ
F
+V
p
IN2
+
IN1
+
IN3
+
IN4
+
BTL4/3
+
SE3
−
BTL3/4
MODE2
BTL1/2
VOL.Sgnd
MUTE
MODE1
SB ON
OFF
CIV
TVA
SVF
1
1
ON
−
SE4
+
+
SE2
−
+
SE1
−
