AD1865

REV. 0

–8–

18-BIT CD PLAYER DESIGN

Figure 10 illustrates an 18-bit CD player design incorporating

an AD1865 D/A converter, an NE5532 dual op amp and the

SM5813 digital filter chip manufactured by NPC. In this de-

sign, the SM5813 filter transmits left and right digital data to

both channels of the AD1865. The left and right latch signals,

LL and LR, are both provided by the word clock signal

(WCKO) of the digital filter. The digital filter supplies data at

an 8

× F

The digital data is converted to analog output voltages by the

output amplifiers on the AD1865. Note that no external compo-

nents are required by the AD1865. Also, no deglitching cir-

cuitry is required.

An NE5532 dual op amp is used to provide the output antialias

filters required for adequate image rejection. One 2-pole filter

section is provided for each channel. An additional pole is cre-

ated from the combination of the internal feedback resistors

nominal 3 k

Ω R

place a pole at approximately 147 kHz, effectively eliminating

all high frequency noise components.

Low distortion, superior channel separation, low power con-

sumption and a low parts count are all realized by this simple

design.

2

4

5

6

1

3

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

AD1865

TRIM

MSB

SJ

DL

LL

DGND

AGND

TRIM

MSB

LR

CLK

DR

AGND

SJ

1

2

3

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

C1

C2

1

2

3

4

5

6

7

8

LEFT

CHANNEL

OUTPUT

RIGHT

CHANNEL

OUTPUT

–5V ANALOG SUPPLY

+5V ANALOG SUPPLY

+5V DIGITAL

SUPPLY

BCKO

WCKO

DOL

DOR

DG

OW20

SM5813AP/

APT

NC

NE5532

OW18

Figure 10. Complete 8

× F