Low-Cost, SOT23, Micropower, High-Side

Current-Sense Amplifier with Voltage Output

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7

critical, use the alternative solution shown in Figure 2.

This solution uses copper PC board traces to create a

sense resistor. The resistivity of a 0.1-inch-wide trace of

2-ounce copper is about 30m

Ω/ft. The resistance tem-

perature coefficient of copper is fairly high (approxi-

mately 0.4%/°C), so systems that experience a wide

temperature variance must compensate for this effect.

In addition, self-heating will introduce a nonlinearity

error. Do not exceed the maximum power dissipation of

the copper trace.

For example, the MAX4372T (with a maximum load cur-

Ω) creates a full-scale

inch-wide copper trace.

Table 1. Recommended Component Values

FULL-SCALE LOAD

CURRENT,

GAIN

(V/V)

CURRENT-SENSE

RESISTOR,

2.0

FULL-SCALE OUTPUT

VOLTAGE (FULL-SCALE

5.0

10.0

0.1

1000

20

100

50

2.0

100

50

5.0

10.0

1

100

20

2.0

100

50

5.0

2.0

100

50

5.0

10.0

5

20

20

10.0

10

10

20

0.1in COPPER

0.3in COPPER

0.3in COPPER

INPUT

LOAD/BATTERY

GND

+2.7V TO +28V

RS+

RS-

OUT

MAX4372T/F/H

Figure 2. Connections Showing Use of PC Board

Chip Information

TRANSISTOR COUNT: 225