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

current enables precision current sensing in applications where the sensed current is small or in 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 meet the maximum values specified in Electrical Characteristics.

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 is selected based on the desired signal-to-noise ratio and other

system requirements of the design.

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

are excellently matched, although the absolute values can vary significantly. TI does not recommend adding

additional resistance around the INAx290 to change the effective gain because of this variation. Table 7-1

describes the typical values of the internal gain resistors seen in the functional diagram above.

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-

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

The INAx290A1 gain offset is ±25 µV and this device is capable of measuring a wide dynamic range of current

up to 92 dB.

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INA290, INA2290, INA4290

SBOS961C – JUNE 2020 – REVISED JUNE 2021

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