INA210-215EVM Circuit
3.6
Voltage Inputs
The V
IN+
and V
IN–
terminals of T2 are intended to be used if the designer is configuring the EVM for
measurement without an onboard shunt resistor (see
). These inputs accept a differential voltage
that is amplified by the selected device gain and is presented at the V
OUT
terminal of T2. 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.
V
IN
and Load terminals of T1 are intended to be used if the user configures the EVM for measurement with
a shunt resistor (see
). The common-mode voltage should be connected to the V
IN
terminal and
the load should be connected to the Load terminal. The shunt can be installed in R1, R2, or the prototype
area, and wired to the R2 footprint. As in the setup for the measurement without a shunt resistor, the input
voltage range and polarity are determined by the supply voltage, reference voltage, and the gain of the
selected device.
3.7
Miscellaneous
The REF terminal of T3 allows the user to configure the INA210-215EVM for either unidirectional or bi-
directional operation
Two easily accessible oscilloscope ground pads are located on the board to facilitate easier probing.
4
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.
4.1
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 +5V. 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 V
IN–
/Load. If
the reference is set to +5V, the output is set near +5V with no input voltage, and responds to input
voltages that are negative with respect to V
IN–
/Load.
4.2
Bi-directional Mode
Bi-directional
refers to a load current that flows in both directions.
shows I
S
flowing 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.
10
INA210-215EVM User's Guide
SBOU065A – August 2008 – Revised June 2014
Copyright © 2008–2014, Texas Instruments Incorporated
