DIO2186

Version 1.0, Apr 2026

www.dioo.com

© 2026 Dioo Microcircuits Co., Ltd. Jiangsu

16

Figure 16. Microamp current measurement

9.6. Design requirements

The design requirements for the circuit is shown below.

Table 1. Design parameters

Symbol

Design parameter

Example value

VS

Power-supply voltage

5 V

VCM

Bus supply rail

12 V

IMI

Minimum sense current

1 µA

IMAX

Maximum sense current

150 µA

Gain

Device gain

25 V/V

VREF

Reference voltage

0 V

9.6.1. Detailed design procedure

The maximum value of the current-sense resistor is calculated based on choice of gain, value of the

maximum current the be sensed (IMAX), and the power-supply voltage (VS). When operating at the maximum

current, the output voltage should be less than the positive output swing specification VSP.

Gain

I

V

R

MAX

SP

Shunt

×

<

(6)

However, a resistance value of 1 kΩ must be used as this value exceeds the maximum recommended

value of RShunt. When operating at the minimum current value, IMIN the output voltage must be greater than

the swing to GND (VSN). In this situation, the output voltage at the minimum current can be calculated to be

25 mV, which is greater than the value for VSN.

Gain

R

I

V

SENSE

MIN

OUTMIN

×

×

=

(7)