Datasheet
INA21x
V+
OUT
GND
IN-
IN+
PRODUCT R and R
3 4
INA210
INA211
INA212
INA213
INA214
5kW
2kW
1kW
20kW
10kW
C
BYPASS
NOTE: 1M paths from shunt inputs to reference and INA21x outputs.W
Shutdown
Control
REF
Reference
Voltage
1MW
R
3
1MW
R
4
Supply Load
R
SHUNT
Output
INA210, INA211
INA212, INA213
INA214
SBOS437E –MAY 2008–REVISED JUNE 2013
www.ti.com
SHUTTING DOWN THE INA210-INA214 SERIES
While the INA210-INA214 series does not have a shutdown pin, its low power consumption allows powering from
the output of a logic gate or transistor switch that can turn on and turn off the INA210-INA214 power-supply
quiescent current.
However, in current shunt monitoring applications. there is also a concern for how much current is drained from
the shunt circuit in shutdown conditions. Evaluating this current drain involves considering the simplified
schematic of the INA210-INA214 in shutdown mode shown in Figure 25.
Figure 25. Basic Circuit for Shutting Down INA210-INA214 with Grounded Reference
Note that there is typically slightly more than 1MΩ impedance (from the combination of 1MΩ feedback and 5kΩ
input resistors) from each input of the INA210-INA214 to the OUT pin and to the REF pin. The amount of current
flowing through these pins depends on the respective ultimate connection. For example, if the REF pin is
grounded, the calculation of the effect of the 1MΩ impedance from the shunt to ground is straightforward.
However, if the reference or op amp is powered while the INA210-INA214 is shut down, the calculation is direct;
instead of assuming 1MΩ to ground, however, assume 1MΩ to the reference voltage. If the reference or op amp
is also shut down, some knowledge of the reference or op amp output impedance under shutdown conditions is
required. For instance, if the reference source behaves as an open circuit when it is unpowered, little or no
current flows through the 1MΩ path.
Regarding the 1MΩ path to the output pin, the output stage of a disabled INA210-INA214 does constitute a good
path to ground; consequently, this current is directly proportional to a shunt common-mode voltage impressed
across a 1MΩ resistor.
As a final note, when the device is powered up, there is an additional, nearly constant, and well-matched 25μA
that flows in each of the inputs as long as the shunt common-mode voltage is 3V or higher. Below 2V common-
mode, the only current effects are the result of the 1MΩ resistors.
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Product Folder Links: INA210 INA211 INA212 INA213 INA214