OP113/OP213/OP413

Rev. F | Page 16 of 24

8

1

4

3

2

2

OUTPUT

+

12V

R1

5kΩ

R2

5kΩ

C2

1µF

R3

2.5kΩ

C1

0.1µF

R4

100Ω

–

+

1/2

OP213

Figure 46. False Ground Generator

LOW NOISE VOLTAGE REFERENCE

Few reference devices combine low noise and high output drive

capabilities. Figure 47 shows the OPx13 family used as a two-

pole active filter that band limits the noise of the 2.5 V reference.

Total noise measures 3 μV p-p.

8

1

4

3

2

1/2

OP213

5V

–

+

OUTPUT

2.5V

+

10kΩ

10kΩ

6

2

5V

IN

OUT

4

GND

REF43

–

+

3µV p-p NOISE

10µF

C2

10µF

Figure 47. Low Noise Voltage Reference

5 V ONLY STEREO DAC FOR MULTIMEDIA

The OPx13 family’s low noise and single supply capability are

ideally suited for stereo DAC audio reproduction or sound

synthesis applications such as multimedia systems. Figure 48

shows an 18-bit stereo DAC output setup that is powered from a

single 5 V supply. The low noise preserves the 18-bit dynamic

range of the AD1868. For DACs that operate on dual supplies,

the OPx13 family can also be powered from the same supplies.

18-BIT

DAC

18-BIT

DAC

AGND

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

LL

DL

CK

DR

LR

DGND

AD1868

8

1

47kΩ

+ –

100pF

7.68kΩ

7.68kΩ

7.68kΩ

7.68kΩ

330pF

9.76kΩ

330pF

9.76kΩ

6

5

7

100pF

47kΩ

+ –

5V SUPPLY

1/2

OP213

1/2

OP213

18-BIT

SERIAL

REG.

18-BIT

SERIAL

REG.

–

+

+

+

220µF

LEFT

CHANNEL

OUTPUT

+

–

–

+

3

2

4

RIGHT

CHANNEL

OUTPUT

220µF

Figure 48. 5 V Only 18-Bit Stereo DAC