OPA378

ADS8325

Load

V

I C

2

R

1

4.99kW

R

3

4.99kW

R

4

48.7kW

R

2

49.9kW

+5V

3V

REF3330

R

7

1.18kW

R

SHUNT

1W

R

6

71.5kW

R

N

56W

R

N

56W

(PGAGain=4)

FS=3.0V

StrayGround-LoopResistance

I

LOAD

R

100

S

W

C

7nF

1

OPA378

Output

R

SHUNT

Load

V+

V+

R

G

R

L

R

(2)

1

10kW

R

BIAS

+5V

zener

(1)

Twozener

biasingmethods

areshown.

(3)

MOSFETratedto

stand-offsupplyvoltage

suchasBSS84for

upto50V.

R

SHUNT

C

BYPASS

OPA378

OPA2378

NOTE: 1% resistors provide adequate common-mode rejection at small ground-loop errors.

Figure 31. Low-Side Current Monitor

(1) Zener rated for op amp supply capability (that is, 5.1V for the OPA378).

(2) Current-limiting resistor.

(3) Choose zener biasing resistor or dual NMOSFETs (FDG6301N, NTJD4001N, or Si1034).

Figure 32. High-Side Current Monitor

Copyright © 2008–2009, Texas Instruments Incorporated

Submit Documentation Feedback

13

Product Folder Link(s): OPA378 OPA2378