INA282 Current Sensor

Overview

The INA282 IC comes in two different SMDSurface Mount Device packages: a SOICSmall Outline Integrated Circuit-8 with a size of 4.90mm x 3.91mm (LxW, excluding pin length) or a smaller VSSOPVery-Thin Shrink Small-Outline Package. Also referred to MSOP (Micro Small-Outline Package)-8 with a size of 3.00mm x 3.00mm (LxW, excluding pin length).

The INA282 is part of the INA28x series that also includes the INA283, INA284, INA285, and INA286 ICs with the same 8-pin configuration and chip packages (SOIC, VSSOP) but different gains shown in the table below.

Pin Descriptions

Operation

The INA282 IC measures input current (I_S) that goes through an external shunt resistor (R_S) and outputs a proportional analog voltage (OUT) with a gain of 50 V/V. The gain is how much the shunt resistor voltage is amplified.

The INA282 IC power supply V+ has a range of (+2.7V to +18V) and is independent of the load power supply (-14V to +80V). A power supply bypass capacitor is required for stability (typically 0.1μF).

The load current I_S is drawn from load power supply through the shunt resistor R_S. The voltage drop across shunt resistor is first fed into an input stage amplifier, then to a zero-drift amplifier that shifts the output voltage (OUT) around a reference voltage (REF1 and REF2 pins).

The reference pins, REF1 and REF2, are used to set the zero point output to (REF1 + REF2)/2. The REF1 and REF2 pins cannot be connected to any voltage source lower than GND or higher than V+ and the reference voltage (REF1 + REF2)/2 must be 9V or less. There are three reference voltages modes used that are commonly used.

Ground Referenced Output:

(REF1=REF2=GND) If REF1 and REF2 are both connected to ground, then the INA282 will be in unidirectional operation where 0V differential across the shunt resistor will produce a 0V output. The input current flows from V_IN+ to V_IN-.

V+ Referenced Output:

(REF1=REF2=V+) The V+ referenced output can be used for unidirectional reversed input currents that flows from V_IN- to V_IN+.

Bidirectional Operation:

(REF1=V+ & REF2=GND) Bidirectional operation can be configured by connecting REF1 to V+ (or some other voltage) and REF2 to ground, where the output voltage moves up/down from the reference voltage REF1 (within the supply rails) for positive/negative currents.

Reference pin connection options are provided in section 7.4.1 of the INA282 Datasheet (PDF).

Specs

Overview

Breakout boards for the INA282 IC are available with external circuitry and pin through holes to make it easy to interface to. The module shown below has a simple board layout with only three components: the INA282 IC, power supply bypass capacitor, and a 0.1Ω 1% tolerance shunt resistor.

Board Layout

The INA282 module board layout is shown in the figure below. This board comes 6-pin through holes to solder on a 6-pin male header to attach this sensor to a breadboard. On the other end of the board are 2 input holes to solder a terminal plug to easily connect and disconnect your load.