DIO2186

Version 1.0, Apr 2026

www.dioo.com

© 2026 Dioo Microcircuits Co., Ltd. Jiangsu

14

LP

L

dB

3

C

×

×

π

4

1

=

f

P

R

(5)

Where:

f3dB is -3dB bandwidth.

RLP is the low-pass filter resistance.

CLP is the low-pass filter capacitance.

As the voltage drop across the sense resistor (VShunt) increases, the amount of voltage dropped across the

input filter resistors (RLP) also increases. The increased voltage drop results in additional gain error. The

error caused by these resistors can be calculated by the resistor divider.

100

R

R

R

1

Error(%)

IN

Shunt

IN





















(5)

Where:

RIN is the differential input impedance.

RLP is the added value of the series filter resistance.

The input stage of the DIO2186 uses a capacitive feedback amplifier topology in order to achieve high DC

precision. As a result, periodic high-frequency shunt voltage (or current) transients of significant amplitude

and duration may be amplified by the DIO2186, even though the transients are greater than the device

bandwidth. Use a differential input filter in these applications to minimize disturbances at the DIO2186

output.

The high input impedance and low bias current of the DIO2186 provide flexibility in the input filter design

without impacting the accuracy of current measurement. For example, set RLP = 100 Ω and CLP = 22 nF to

achieve a low-pass filter corner frequency of 36.2 kHz. These filter values significantly attenuate most

unwanted high-frequency signals at the input without severely impacting the current sensing bandwidth or

precision. If a lower corner frequency is desired, increase the value of CLP.

Filtering the input filters out differential noise across the sense resistor. If high-frequency, common-mode

noise is a concern, add an RC filter from the OUT pin to ground. The RC filter helps filter out both

differential and common mode noise, as well as internally generated noise from the device. The value for

the resistance of the RC filter is limited by the impedance of the load. Any current drawn by the load

manifests as an external voltage drop from the DIO2186 OUT pin to the load input.

9.4. Common-mode voltage transients

With a small amount of additional circuitry, the DIO2186 can be used in circuits subject to transients that

exceed the absolute maximum voltage ratings. To protect the inputs from negative transients, it is highly

recommended to add resistors in series with the IN- and IN+ pins. Use resistors (≤ 1 kΩ) and limit the

current in the ESD structures (≤ 5 mA). For example, using 1 kΩ resistors in series with the DIO2186 allows

voltages as low as -5 V, while limiting the ESD current to less than 5 mA. Common-voltage transients is

required when protection from high-voltage positive or negative.

When implementing these circuits, use only Zener diodes or Zener-type transient absorbers (sometimes

referred to as transzorbs); any other type of transient absorber has an unacceptable time delay. Start by

adding a pair of resistors as a working impedance for the Zener diode, and refer to the figure below. Keep