Datasheet

C
BYPASS
0.1µF
5V Supply
Load
Output
-
+
IN-
IN+
GND
V+
OUT
REF
INA210 , INA211 , INA212 , INA213 , INA214 , INA215
SBOS437F –MAY 2008–REVISED JUNE 2014 www.ti.com
9 Application and Implementation
9.1 Application Information
The INA210-INA215 measure the voltage developed across a current-sensing resistor when current passes
through it. The ability to drive the reference pin to adjust the functionality of the output signal offers multiple
configurations, as discussed throughout this section.
9.2 Typical Applications
9.2.1 Unidirectional Operation
Figure 30. Unidirectional Application Schematic
9.2.1.1 Design Requirements
The device can be configured to monitor current flowing in one direction (unidirectional) or in both directions
(bidirectional) depending on how the REF pin is configured. The most common case is unidirectional where the
output is set to ground when no current is flowing by connecting the REF pin to ground, as shown in Figure 30.
When the input signal increases, the output voltage at the OUT pin increases.
9.2.1.2 Detailed Design Procedure
The linear range of the output stage is limited in how close the output voltage can approach ground under zero
input conditions. In unidirectional applications where measuring very low input currents is desirable, bias the REF
pin to a convenient value above 50 mV to get the output into the linear range of the device. To limit common-
mode rejection errors, TI recommends buffering the reference voltage connected to the REF pin.
A less frequently-used output biasing method is to connect the REF pin to the supply voltage, V+. This method
results in the output voltage saturating at 200 mV below the supply voltage when no differential input signal is
present. This method is similar to the output saturated low condition with no input signal when the REF pin is
connected to ground. The output voltage in this configuration only responds to negative currents that develop
negative differential input voltage relative to the device IN– pin. Under these conditions, when the differential
input signal increases negatively, the output voltage moves downward from the saturated supply voltage. The
voltage applied to the REF pin must not exceed the device supply voltage.
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Product Folder Links: INA210 INA211 INA212 INA213 INA214 INA215