Reference Voltage Setup - Texas Instruments INA210-215EVM User Manual

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4.3 Ux01
Ux01 is the location for the test device. Six device boards are supplied with the INA210-215EVM board.
Each board is populated with one of the available device gains. This option allows users to test the
devices and determine the gain setting that is best suited for a given application.
Here is a list of the factors involved in selecting the appropriate device:
• The INA210-215 devices are identical with the exception of different gain settings.
• The differential input voltage is either applied across the inputs or developed based on the load current
that flows through the shunt resistor.
• The limiting factor that requires attention to be given to device selection is the output voltage.
• The selected device must allow the output voltage to remain within the acceptable range after the
developed input voltage is amplified by the respective device gain. The output voltage must remain
with the range of 50 mV above ground to 200 mV below the supply voltage.
• An output below the minimum allowable output requires the selection of a device with a higher gain.
Likewise, an output above the maximum allowable output requires the selection of a device with a
lower gain.
4.4 Voltage Inputs
The IN+ (TPx03 or TPx13) and IN– (TPx04 or TPx14) inputs accept a differential voltage that is amplified
by the selected device gain and is presented at the OUT test point (TPx06 or TPx16). These inputs could
also be used to connect the differential voltage developed across an external shunt in an existing circuit.
The acceptable differential input voltage range and polarity are determined by the supply voltage,
reference voltage, and gain of the selected device.
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Reference Voltage Setup

The INA210-215 devices allow for the use of an external reference. This reference determines how the
output responds to certain input conditions. The reference also allows these devices to be used in both
unidirectional and bi-directional applications.
5.1 Unidirectional Mode
Unidirectional refers to a load current that flows in only one direction. For unidirectional applications, the
reference voltage can be set to ground or to 5 V. If the reference is set to ground, the output is set at near
ground with no input voltage, and responds to input voltages that are positive with respect to IN– /Load. If
the reference is set to 5 V, the output is set near 5 V with no input voltage, and responds to input voltages
that are negative with respect to IN– /Load.
5.2 Bi-Directional Mode
Bi-directional refers to a load current that flows in both directions. For bi-directional applications, the
reference voltage can be set anywhere within the 0-V to 5-V range specified for the reference input. The
voltage applied to the reference pin establishes the output voltage of the device with no input voltage. The
output voltage is limited by the supply voltage, so there is a greater available range for positive input
voltages than negative voltages because the reference voltage is limited to the range of 0 V to 5 V.
The maximum range for the output of this device to accommodate a bi-directional application involves
applying 5 V to the reference pin and a supply voltage of 18 V. This configuration allows for a maximum
output voltage range of –4.95 V/20.8 V about the 5-V reference.
SBOU164 – July 2016
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INA210-215EVM Circuit
INA210-215EVM User's Guide
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