TDA8947J Datasheet, PDF (17/24 Pages) NXP Semiconductors – 4-channel audio amplifier (SE: 1 W to 25 W; BTL: 4 W to 50 W)

Philips Semiconductors
TDA8947J
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.
220 nF
4Ω
4Ω
4Ω
TVA
100 nF
1
220 nF
4.7 nF
AUDIO POWER CS NIJMEGEN
1
CIV
SVF
22
220 _µF
µF
220 nF
220 nF
4Ω
4Ω
220 nF
4Ω
+ Vp
IN2+
IN1+
IN3+
150
µF
MODE1
IN4+
10 kΩ
VOL.Sgnd
10 kΩ
SB ON
MUTE
OFF
ON
Fig 14. Printed-circuit board layout (single-sided); components view.
MCE483
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 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 µF 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 THD and noise performance a low ESR capacitor is recommended.
9397 750 10779
Preliminary data
Rev. 01 — 06 February 2004
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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