AD1857/AD1858

REV. 0

–13–

14

13

12

11

17

16

15

20

19

18

10

9

8

1

2

3

4

7

6

5

DIGITAL

GROUND

PLANE

MCLK

SDATA

L

RCLK

BCLK

PD/RST

MODE

NC

MUTE

DGND

DEEMP

384/

256

OUTL

AGND

CMOUT

FILT

AGND

OUTR

ANALOG

GROUND

PLANE

NC = NO CONNECT

FERRITE

BEAD

Figure 22. Recommended Ground Plane

Layout and Decoupling Considerations

The recommended decoupling, bypass and output circuits for

the AD1857/AD1858 are shown in Figure 21.

PCB and Ground Plane Recommendations

The AD1857/AD1858 ideally should be located above a split

ground plane, with the digital pins over the digital ground plane

and the analog pins over the analog ground plane. The split

should occur between Pins 6 and 7, and between Pins 14 and

15 as shown in Figure 22. The ground planes should be linked

with a ferrite bead. This ground plane strategy maximizes the

AD1857/AD1858’s analog audio performance.

2.2

µF

RIGHT LINE

OUTPUT

LEFT LINE

OUTPUT

AGND

FILT

CMOUT

+5V

ANALOG

SDATA

BLCK

L

RCLK

MODE

AGND

DGND

+5V

DIGITAL

OUTL

OUTR

MUTE

DEEMP

NC

PD/RST

BIAS VOLTAGE

FOR EXTERNAL

USE

+5V

ANALOG

NC = NO CONNECT

0.1

µF

4.7

µF

0.1

µF

4.7

µF

AD1857/AD1858

MCLK

256 MODE

384 MODE

SAMPLE RATE

12.288MHz

18.432MHz

48kHz

44.1kHz

32kHz

11.2896MHz

16.9344MHz

8.192MHz

12.288MHz

384/

256

MCLK FREQUENCY

384/

256 = LO 384/256 = HI

DSP OR

AUDIO

DECODER

0.1

µF

2.2

µF

µCONTROLLER

4.7

µF

0.01

µF

12

11

8

13

10

9

7

14

1

6

18

19

3

20

16

2

15

5

4

17

4.7

µF

RIGHT LINE

OUTPUT

LEFT LINE

OUTPUT

OUTL

OUTR

2.2

µF

8

13

100k

820pF

1k

Ω

+

2.2

µF

100k

820pF

1k

Ω

+

*OPTIONAL OUTPUT FILTER

*

*

Figure 21. Recommended Circuit Connection