OPA688M

UNITY GAINSTABLE WIDEBAND

VOLTAGE LIMITING AMPLIFIER

SGLS144B − APRIL 2003 − DECEMBER 2006

13

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

OPA688

57.6

Ω

6

I VH

V H = 3.7V

V

O

V

L = 1.3V

V IN

I VL

806

Ω

3

2

4

7

8

5

806

Ω

523

Ω

976

Ω

523

Ω

R G

402

Ω

R F

402

Ω

500

Ω

0.1

∝ F

0.1

∝ F

0.1

∝ F

2.2

∝ F

0.1

∝ F

V S = +5V

0.1

∝ F

0.1

∝ F

Figure 31. AC-Coupled, Single Supply Amplifier

OP A 6 8 8

V S =+ 5 V

4

2

3

7

5

8

6

V S =+ 5 V

+3 . 5 V

+1 . 5 V

V IN

RE F B

RE F T

IN

0. 1

∝ F

10 0 p F

V H = + 3. 6V

V L =+ 1 . 4 V

0. 1

∝ F

0. 1

∝ F

0. 1

∝ F

40 2

Ω

24 . 9

Ω

562

Ω

102

Ω

40 2

Ω

71 5

Ω

71 5

Ω

10 2

Ω

56 2

Ω

AD S 8 2 2

10 −B i t

40 M S P S

10−B i t

Da t a

V S =+ 5 V

IN T / E X T

RS E L

+ V

S

GN D

Figure 32. Single Supply, Limiting ADC Input Driver

precision half wave rectifier

Figure 33 shows a half wave rectifier with outstanding precision and speed. VH (pin 8) will default to a voltage

between 3.1 and 3.8 V if left open, while the negative limit is set to ground.