Texas Instruments INA168NA/3KG4

Overview

INA168NA/3KG4 from Texas Instruments is a unipolar high-side current shunt monitor IC designed for precision measurement of load current via a sense resistor in systems with common-mode voltages up to 60 V. It features 200 µA/V transconductance, ±1 mV max offset voltage at 25°C, 25 µA quiescent current, and operates across –40°C to +125°C. It is used in battery chargers and power management circuits where supply and input common-mode voltages are independent.

For engineers reviewing the INA168NA/3KG4 datasheet, INA168NA/3KG4 pinout, INA168NA/3KG4 application, or INA168NA/3KG4 equivalent, key selection criteria include its 60 V common-mode range, single-resistor gain configuration, current-output architecture, low quiescent current, and SOT-23-5 packaging for space-constrained high-voltage monitoring.

Technical Context

The INA168NA/3KG4 implements a high-voltage precision op amp with trimmed thin-film resistors and a low-noise output transistor, enabling accurate differential voltage-to-current conversion. Its input stage supports common-mode voltages up to 60 V while operating from a 2.7 V to 60 V supply - independent of VIN+ and VIN–.

It delivers 200 µA/V transconductance with ±0.1% nonlinearity over 10–150 mV input range and maintains 100 dB minimum common-mode rejection across 0.1 Hz–100 kHz. Output compliance is governed by two limits: (V+) – 0.7 V – VSENSE and VIN– – 0.5 V.

Key Specifications

Pinout & Package

INA168NA/3KG4 is housed in a 5-pin SOT-23 package (2.90 mm × 1.60 mm), optimized for high-density PCB layouts in portable and industrial power systems.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side current measurement applications.

Compared with INA240A1IDR and MAX4080TASA+, the INA168NA/3KG4 uniquely balances ultra-low quiescent current (25 µA), 60 V common-mode capability, and programmable gain via RL - making it optimal for cost-sensitive, space-constrained, always-on monitoring in 24–48 V systems.

Availability

INA168NA/3KG4 is available at Aetrix Electronics and suitable for battery chargers, 48 V telecom power systems, and industrial motor drive feedback requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for INA168NA/3KG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in precision signal chain and power management solutions.

The INA168NA/3KG4 belongs to TI's high-side current sense amplifier product line, engineered specifically for unipolar current monitoring in high-common-mode-voltage applications such as power supplies, battery management, and industrial controls.

FAQ

What is the maximum common-mode voltage supported by the INA168NA/3KG4?

The INA168NA/3KG4 supports an input common-mode voltage range of 2.7 V to 60 V. This specification is explicitly confirmed in the Recommended Operating Conditions table of the SBOS122E datasheet. The device maintains accuracy and stability across this full range, enabling direct integration into 48 V systems without attenuation or level-shifting circuitry. Exceeding 60 V risks violating absolute maximum ratings and may cause permanent damage.

How does the INA168NA/3KG4 generate its output signal?

The INA168NA/3KG4 is a transconductance amplifier that outputs a current proportional to the differential input voltage (VIN+ – VIN–), with a nominal transconductance of 200 µA/V. This current flows out of the OUT pin and must be converted to a voltage using an external load resistor (RL) connected to ground. The resulting output voltage is VOUT = (VIN+ – VIN–) × 200 µA/V × RL. This architecture decouples gain setting from the IC itself and avoids loading effects on the sense node.

Can the INA168NA/3KG4 measure bidirectional current?

No - the INA168NA/3KG4 is specified and characterized only for unipolar operation, requiring VIN+ to be more positive than VIN–. Attempting reverse polarity results in zero output current, though it will not damage the device. For bidirectional measurement, TI recommends dual-INA configurations (e.g., one INA168NA/3KG4 per polarity) with external logic or comparators, as detailed in Figure 15 of the SBOS122E datasheet.

What is the recommended external load resistor (RL) range for the INA168NA/3KG4?

The SBOS122E datasheet confirms stable operation with RL values from 5 kΩ to 500 kΩ. Lower RL (e.g., 5 kΩ) yields higher bandwidth (800 kHz) but lower gain; higher RL (e.g., 500 kΩ) provides gain up to 100 V/V but reduces bandwidth to ~3.2 kHz. RL selection must also respect output compliance limits: VOUT ≤ (V+) – 0.7 V – VSENSE and VOUT ≤ VIN– – 0.5 V. Typical designs use 25 kΩ–125 kΩ for balanced gain and speed.

Does the INA168NA/3KG4 require a separate ground connection for the power supply?

Yes - the INA168NA/3KG4 has a dedicated GND pin (Pin 2) that must be connected to the system ground reference. Although V+ and input common-mode voltages are independent, internal circuitry requires this ground return path for biasing and output current sinking. Failure to connect GND will result in undefined behavior or complete functional failure. The GND connection is not optional and cannot be omitted even in floating supply configurations.