OPA348, 2348, 4348

9

SBOS213C

www.ti.com

FIGURE 8. OPA2348 as a Speech Bandpass Filtered Data Acquisition System.

FIGURE 7. OPA348 in Noninverting Configuration Driving ADS7822.

ADS7822

12-Bit A/D

DCLOCK

D

OUT

CS/SHDN

OPA348

+5V

V

IN

V+

2

+In

3

–In

V

REF

8

4

GND

Serial

Interface

1

0.1

µF

0.1

µF

7

6

5

NOTE: A/D Input = 0 to V

REF

V

0V to 5V output.

RC network filters high frequency noise.

500

Ω

3300pF

C

3

33pF

V+

GND

3

1

8

4

5

6

7

–IN

+IN

2

C

2

DCLOCK

Serial

Interface

1000pF

R

1

1.5k

Ω

R

4

20k

Ω

R

5

20k

Ω

R

6

100k

Ω

R

8

150k

Ω

R

9

510k

Ω

R

7

51k

Ω

D

OUT

V

REF

V+ = +2.7V to 5V

CS/SHDN

1000pF

Electret

G = 100

Passband 300Hz to 3kHz

R

3

1M

Ω

R

2

1M

Ω

NOTE: (1) Electret microphone

powered by R

ADS7822

12-Bit A/D

1/2

OPA2348

1/2

OPA2348