8.2 Typical Application

14

13

INA

OUTD

3

4

5

6

0.1 F

EN1

EN2

7

10

INB

12

11

OUTC

IND

IN

C

DVDD

DGND

2

GAIN1

24

25

26

GAIN0

SPEED

PWDN

AIN3+

AIN3–

AIN4+

A0

A1

AIN1+

AIN1–

AIN2+

SCLK

DOUT

REF+

REF–

AIN4–

1

VCC1

16

VCC2

2, 8

9, 15

GND1

GND2

23

20

19

28

8

7

27

0.1 F

P3.1

P3.0

CLK

SOMI

13

11

12

14

4

2

MSP430F2132

DVss

DVcc

0.1 F

14

13

OUTD

3

4

5

6

0.1 F

NC

EN

7

10

12

11

OUTC

IND

IN

C

1

VCC1

16

VCC2

2, 8

9, 15

GND1

GND2

0.1 F

ISO7840

ISO7841

5VISO

5VISO

3.3V

3.3V

P3.7

P3.6

18

17

3.3V

22

AVDD

AGND

21

5VISO

0.1 F

AIN2–

13

14

17

16

15

11

12

18

INA

INB

OUTB

OUTA

OUTA

OUTB

1

0.1 F

0.1 F

5VISO

5 VISO

Thermo

couple

Current

shunt

RTD

Bridge

XOUT

XIN

5

6

P3.4

15

P3.5

16

ADS1234

Isolation

Barrier

GND

Figure 8-1. Isolated Data Acquisition System for Process Control

8.2.1 Design Requirements

For this design example, use the parameters shown in Table 8-1.

Table 8-1. Design Parameters

PARAMETER

VALUE

Supply voltage

2.25V to 5.5V

Decoupling capacitor between VCC1 and GND1

0.1µF

Decoupling capacitor from VCC2 and GND2

0.1µF

8.2.2 Detailed Design Procedure

Unlike optocouplers, which require external components to improve performance, provide bias, or limit current,

the ISO7840 device only requires two external bypass capacitors to operate.

www.ti.com

ISO7840, ISO7840F

SLLSEN2C – JULY 2015 – REVISED JULY 2025

Copyright © 2025 Texas Instruments Incorporated

Submit Document Feedback

21

Product Folder Links: ISO7840 ISO7840F