SA58670A NXP Semiconductors, SA58670A Datasheet - Page 16

• Manufacturer Part Number: SA58670A
• Manufacturer: NXP Semiconductors

NXP Semiconductors
11. Application information
SA58670A_2
Product data sheet
11.1 Power supply decoupling considerations
11.2 Input capacitor selection
The SA58670A is a stereo class-D audio amplifier that requires proper supply voltage
decoupling to ensure the rated performance for THD+N and power efficiency. To decouple
high frequency transients, supply voltage spikes and digital noise on the supply voltage
bus line, a low Equivalent Series Resistance (ESR) capacitor of typically 1 F is placed as
close as possible to the PVDD pins of the SA58670A. It is important to place the
decoupling capacitor at the supply voltage pins of the SA58670A because any resistance
or inductance in the PCB trace between the SA58670A and the capacitor can cause a
loss in efficiency. Additional decoupling using a larger capacitor, 4.7 F or greater, may be
done on the supply voltage connection on the PCB to filter low frequency signals. Usually
this is not required due to high PSRR of the SA58670A.
The SA58670A does not require input coupling capacitors when used with a differential
audio source that is biased from 0.5 V to V
be biased within the common-mode input voltage (V
required or if it is driven using a single-ended source, input coupling capacitors are
required.
The 3 dB cut-off frequency created by the input coupling capacitor and the input resistors
(see
f
Fig 16. SA58670A application schematic
–
3dB
Table
=
V
----------------------------- -
2
DD
6) is calculated by
R
1
10 F
i
C
V
1 nF
1 nF
DD
i
Rev. 02 — 23 October 2008
FB
FB
1 F
1 F
G1
OUTLP
OUTLN
PVDD
PGND
differential inputs
INLP
left channel
Equation
INLN
SDL
1 F
SA58670A
1:
AGND
2.1 W/channel stereo class-D audio amplifier
DD
SDR
1 F
differential inputs
0.8 V. In other words, the input signal must
right channel
INRN
AVDD
i(cm)
1 F
INRP
OUTRP
OUTRN
PGND
PVDD
) range. If high-pass filtering is
1 F
G0
10 F
FB
FB
V
DD
1 F
SA58670A
V
1 nF
1 nF
DD
© NXP B.V. 2008. All rights reserved.
10 F
002aad665
V
DD
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