3 Operation
3.1 Quick Start Setup
Follow these procedures to set up and use one of the INA2191EVM panels. For these instructions, n is gain
option 1, 2, 3, 4, or 5.
1. Choose the desired gain option by choosing the panel with the label showing the desired gain.
2. Choose the settings for the enable (EN1 and EN2) and reference (REF1 and REF2) pins using jumpers
JA2n and JA1n for the enable pins and J5n and J6n for the reference pins.
3. Shorting an enable pin to the supply voltage (Vs) turns the device's corresponding channel on, while shorting
the enable pin to ground turns this channel off.
4. Shorting the reference pin to ground biases the output of the corresponding channel to ground, while
shorting the reference pin to Vs/2 pin biases the output of the corresponding channel to mid-supply. Note
that the on-board Vs/2 voltage is available to easily bias the device with no extra source; however, it is
best practice to drive the reference pin with a low-impedance voltage source and thus inserting a buffer in
between Vs/2 and the reference pin will ensure performance according to device datasheet specifications.
5. Connect an external DC supply voltage (between 1.7 V and 5.5 V) to a VS test point. Connect the ground
reference of that supply to a GND test point on the same panel.
6. Provide a differential input voltage signal across the input pins and ensure the common-mode voltage (V
CM
)
of this differential signal is within the operational V
CM
rating of the device.
a. The differential signal should be supplied across the input pins by driving the signal across J1n and J2n
for channel 1 or J3n and J4n for channel 2 on the EVM, as explained in
.
7. Check to make sure all grounds of the sources and EVM are common and connected with low-impedance
connections.
3.2 Measurements
The user can either emulate the voltage developed across a sense resistor based on a given set of system
conditions with the INA2191EVM, or connect the device inputs to an external shunt resistor. The user can also
solder a surface-mount technology (SMT) shunt resistor across the Rs+ and Rs– pads, and these inputs can be
connected in series with the external system and load.
Note the following where n is gain option 1, 2, 3, 4, or 5.
• Each device channel has its own pads for an optional shunt resistor
– Rs1n is shunt resistor for channel 1, while Rs2n is the shunt resistor for channel 2.
– When running current through Rs1 or Rs2, the user can connect the load and source to the shunt resistor
using the quick-connect tabs J1n and J2n for Rs1n or J3n and J4n for Rs2n.
– All shunt resistors will be referred to as Rshunt.
• Each device channel has its own input pins with test points
– IN1+ and IN1– are the silkscreen markings for channel 1 input pins IN+1 and IN–1 respectively.
– IN2 + and IN2– are the silkscreen markings for channel 2 input pins IN+2 and IN–2 respectively.
– All input nodes will be referred to as IN+ and IN– or just as input pins.
• Input pins connect to shunt resistor pads for each channel on each gain variant panel
– Rs1+ and Rs1– are the same nets as IN1+ and IN1– respectively for channel 1.
– Rs2+ and Rs2– are the same nets as IN2+ and IN2– respectively for channel 2.
– The shunt resistor and input pin nodes become different once the input resistors (R3n, R4n, R5n, R6n) are
increased to resistance greater than 0 Ω.
To configure a measurement evaluation without a shunt resistor, follow this procedure:
1. Connect a positive differential voltage across the device channel inputs from IN+ to IN– (or Rs1+ to Rs–)
using J1n and J2n tabs for channel 1 and J3n and J4n tabs for channel 2.
a. For any unused channel, short the inputs and tie these inputs to ground or some other valid common-
mode voltage (V
CM
).
2. If the differential supply is floating, then connect a –0.1-V to 40-V V
CM
to the inputs of the device channel.
Connect the positive lead of the V
CM
source to the IN– tab and V
CM
source ground to a GND test point.
Operation
SBOU254A – JANUARY 2021 – REVISED JUNE 2021
INA2191EVM
5
Copyright © 2021 Texas Instruments Incorporated
