Nxp Semiconductors SA58670A 用户手册

SA58670A_2

© NXP B.V. 2008. All rights reserved.

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

µ

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

µ

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

DD

−

0.8 V. In other words, the input signal must

be biased within the common-mode input voltage (V

i(cm)

) range. If high-pass filtering is

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

) is calculated by

(1)

002aad665

OUTRP

OUTRN

10 

µ

F

1 nF

1 nF

FB

FB

1 nF

1 nF

OUTLP

OUTLN

V

DD

G1

V

DD

PVDD

PGND

1 

µ

F

V

DD

10 

µ

F

1 

µ

F

V

DD

SDL

SDR

AVDD

10 

µ

F

1 

µ

F

PGND

V

DD

PVDD

G0

INLP

1 

µ

F

INLN

1 

µ

F

differential inputs

left channel

INRN

1 

µ

F

INRP

1 

µ

F

differential inputs

right channel

AGND

FB

FB

–

π

×

×

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