7 Detailed Description

7.1 Overview

7.1.1 INA151 Transconductance Architecture Overview

The INA151 employs a transconductance-based architecture utilizing current-feedback amplifier topology to

achieve low bias currents of 20μA and a common-mode voltage of 110V above negative supply. The block

diagram illustrated in Figure 7-1 demonstrates the dual-stage approach of this architecture. In the first stage

the differential voltage is translated to a differential current through R1. The differential output current is further

converted into a single-ended output voltage in the second amplifier stage.

The closed-loop voltage gain VOUT/VIN is established by the ratio of the internal precision resistors R3 by

R1. Consequently, gain accuracy is mainly limited by the resistor matching tolerance between the signal paths,

making precision thin-film resistor implementation critical for the performance.

These key architectural features make the INA151 ideally suited for serial stacked battery cell monitoring

applications, enabling precise voltage measurements across up to 20 series-connected battery cells.

The INA151 encompasses four gain variants to address . The INA151A version offers gain option of 1, while

the INA151B, INA151C and INA151D versions offer gain options of ⅔, ½ and ¼ respectively. The multiple gain

variants are designed to accommodate the full-scale input ranges of various ADC requirements, maximizing

measurement resolution and dynamic range.

7.1.2 Multiplexing Capability

The integrated enable/disable control with high-impedance output state facilitates multiplexed operation modes.

This architecture enables parallel connection of multiple INA151 devices with common output nodes, allowing

sequential amplifier selection for single ADC sampling applications through digital enable control.

The INA151 is available in industry standard packages including SOT-23.

7.2 Functional Block Diagram

R1

R1

+

–

+

–

VS

REF

VOUT

VCM

VS+

VCM

VDIFF

Max. ±5V

DGND

EN

VS+

VSub

RS

RS

R3

R3

R2

R2

500k

500k

62.5k

62.5k

Variant A (G=1): 500k

Variant B (G=2/3): 333.33k

Variant C (G=½ ): 250k

Variant D (G=¼): 125k

Figure 7-1. INA151A Simplified Internal Schematic

INA151

SLVSIL6B – JANUARY 2026 – REVISED MARCH 2026

www.ti.com

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