7.3.3 Low Input Bias Current

The INAx290 input bias current draws 20 μA (typical) even with common-mode voltages as high as 120 V. This

enables precision current sensing in applications where the sensed current is small or applications that require

lower input leakage current.

levels accurately across the wide operating temperature of –40 °C to +125 °C. The capability to measure low

sense voltages enables accurate measurements at lower load currents, and also allows reduction of the sense

resistor value for a given operating current, which minimizes the power loss in the current sensing element. For

multichannel devices, the offset voltage and offset drift characteristics can vary from channel to channel;

however, all channels will meet the maximum values specified in Section 6.5.

7.3.5 Wide Fixed Gain Output

The INAx290 gain error is < 0.1% at room temperature for most gain options, with a maximum drift of 5 ppm/°C

over the full temperature range of –40 °C to +125 °C. The INAx290 is available in multiple gain options of 20 V/V,

50 V/V, 100 V/V, 200 V/V, and 500 V/V, which the system designer should select based on their desired signal-

to-noise ratio and other system requirements.

The INAx290 closed-loop gain is set by a precision, low-drift internal resistor network. The ratio of these resistors

are excellently matched, while the absolute values may vary significantly. TI does not recommend adding

additional resistance around the INAx290 to change the effective gain because of this variation, however. The

typical values of the gain resistors are described in Table 7-1.

Table 7-1. Fixed Gain Resistor

GAIN

R1

RL

20 (V/V)

25 kΩ

500 kΩ

50 (V/V)

10 kΩ

500 kΩ

100 (V/V)

10 kΩ

1000 kΩ

200 (V/V)

5 kΩ

1000 kΩ

500 (V/V)

2 kΩ

1000 kΩ

7.3.6 Wide Supply Range

The INAx290 operates with a wide supply range from a 2.7 V to 20 V. The output stage supports a full-scale

measurements. For a gain of 20 V/V, the maximum differential input acceptable is 1 V.

The offset of the gain of INAx290A1 device is ±25 μV, and the INAx290A1 is capable of measuring a wide

dynamic range of current up to 92 dB.

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INA290, INA2290

SBOS961B – JUNE 2020 – REVISED DECEMBER 2020

Copyright © 2020 Texas Instruments Incorporated

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