INA351 datasheet(20/46 Pages) TI

20 / 46 page

7.3 Feature Description

7.3.1 Gain-Setting

Equation 1 is the gain equation for INA351ABS:

G=1+180 kΩRG

(1)

The value of the internal gain resistor RG for INA351ABS can then be derived from the gain equation:

RG=180 kΩG−1

(2)

Similarly, Equation 3 is the gain equation for INA351CDS:

G=1 + 290 kΩRG

(3)

The value of the internal gain resistor RG for INA351CDS can then be derived from the gain equation:

RG= 290 kΩG − 1

(4)

Table 7-1 provides how to choose different gain options across the INA351ABS and INA351CDS. The 60-kΩ,

90-kΩ, and 145-kΩ resistors mentioned are all typical values of the on-chip resistors.

Table 7-1. Gain Selection Table

DEVICE

GAIN SELECT (GS)

SELECTED GAIN

INA351ABS

High or No Connect

Low

INA351CDS

High or No Connect

Low

7.3.1.1 Gain Error and Drift

Gain error in the INA351 is limited by the mismatch of the integrated precision resistors and is specified based

on characterization results. Gain error of maximum 0.1% can be expected for all gains of 10, 20, 30 and 50.

Gain drift in the INA351 is limited by the slight mismatch of the temperature coefficient of the integrated resistors.

Since these integrated resistors are precision matched with low temperature coefficient resistors to begin with,

the overall gain drift is much better in comparison to discrete implementation of the instrumentation amplifiers

built using external resistors.

7.3.2 Input Common-Mode Voltage Range

The INA351 has two gain stages, the first stage has a common-mode gain of 1 and a differential gain set by

the GS pin. The second stage is configured in a difference-amplifier configuration with differential gain of 1 and

ideally rejects all of the input common mode completely. The second stage also provides a gain of 1 from REF

pin to set the output common-mode voltage.

The linear input voltage range of the INA351, even for a rail-to-rail first stage, is dictated by both the signal swing

at output of the first stage as well as the input common-mode voltage range output swing of the second stage.

To maximize performance, it is critical to keep the INA351 within the linear range for a given combination of

gain, reference, and input common-mode voltage for a particular input differential. Input common-mode voltage

(VCM) vs output voltage graphs (VOUT) in this section show a particular reference voltage and gain configuration

to outline the linear performance region of the INA351. A good common-mode rejection can be expected when

operating with in the limits of the VCM vs VOUT graph. Note that the INA351 linear input voltage cannot be close

to or extend beyond the supply rails, as the output of the first stage is driven into saturation.

INA351

SBOSAD5D – DECEMBER 2022 – REVISED NOVEMBER 2024

www.ti.com

Submit Document Feedback

Product Folder Links: INA351

INA351 Datasheet(PDF) 20 Page - Texas Instruments

INA351 Datasheet(HTML) 20 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

Datasheet Download

Link URL