AD1864

–8–

REV. A

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

AD1864

S

+V

L

–V

TRIM

MSB

SJ

DL

LL

DGND

AGND

OUT

V

OUT

I

OUT

I

OUT

V

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

S

+V

LEFT

CHANNEL

OUTPUT

RIGHT

CHANNEL

OUTPUT

–5V ANALOG SUPPLY

+5V ANALOG SUPPLY

+5V DIGITAL SUPPLY

–5V DIGITAL SUPPLY

BCKO

WCKO

DOL

DOR

DG

OW18

OW20

SM5813AP/A

PT

AD712

OR

NE5532

Figure 11. Complete 8

× F

8-BIT CD PLAYER DESIGN

Figure 11 illustrates an 18-bit CD player design incorporating

an AD1864 D/A converter, an AD712 or NE5532 dual op amp

and the SM5813 digital filter chip manufactured by NPC. In

this design, the SM5813 filter transmits left and right digital

data to both channels of the AD1864. 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 AD1864. Note that no external

components are required by the AD1864. Also, no deglitching

circuitry is required.

An AD712 or 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 created from the combination of the internal

For example, the nominal 3 k

Ω RF with a 360 pF capacitor for

C1 and C2 will place a pole at approximately 147 kHz, effec-

tively eliminating all high frequency noise components.

Close matching of the ac characteristics of the amplifiers on the

AD712 as well as their low distortion make it an ideal choice for

the task.

LOW distortion, superior channel separation, low power

consumption and a low component count are all realized by this

simple design.