Texas Instruments INA199C1RSWT

Overview

INA199C1RSWT from Texas Instruments is a bidirectional, zero-drift current-shunt monitor optimized for high-accuracy, low-power current sensing in both high-side and low-side configurations. It features ±150 μV maximum offset voltage, 100 V/V fixed gain, ±1% maximum gain error over temperature, –0.1 V to 26 V common-mode input range, and operates from 2.7 V to 26 V supply with ≤100 μA quiescent current. It enables 10-mV full-scale shunt measurements in notebook power rails and wireless charging transmitters.

For engineers reviewing the INA199C1RSWT datasheet, INA199C1RSWT pinout, INA199C1RSWT application, or INA199C1RSWT equivalent, this page delivers verified technical context, package-specific pin functions, real-world use-value per application, and two validated alternative parts with documented functional and selection differences.

Technical Context

The INA199C1RSWT implements a zero-drift chopper-stabilized amplifier architecture to achieve 0.5 μV/°C max offset drift and 10 ppm/°C max gain drift across –40°C to +125°C. Its differential input stage supports true bidirectional sensing with independent IN+ and IN– terminals referenced to common-mode voltages up to 26 V - exceeding its own 2.7–26 V supply rail.

It uses internal precision resistor networks (R1 = R2 = 1 MΩ, R3 = R4 = 10 kΩ) to set its fixed 100 V/V gain, enabling direct voltage-output scaling of shunt voltage without external gain components. The REF pin allows output level shifting from 0 V to V+, supporting single-supply ADC interfacing with programmable common-mode output alignment.

Key Specifications

Pinout & Package

INA199C1RSWT is packaged in a 10-pin UQFN (RSW) with 1.80 mm × 1.40 mm body size and 0.5-mm pitch. Thermal performance includes R_θJA = 107.3°C/W and R_θJB = 18.7°C/W, supporting high-density PCB layouts with minimal thermal relief.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-sense amplifier applications.

Compared with INA199C1RSWT, INA240A1QDR offers superior offset and automotive qualification but narrower supply range, while MAX40056ATA+T provides higher speed and smaller size but no REF pin - making INA199C1RSWT optimal for wide-rail, REF-flexible, industrial-grade current sensing.

Availability

INA199C1RSWT is available at Aetrix Electronics and suitable for notebook power management, Qi wireless charging transmitters, telecom power conversion, and USB-C PD battery chargers requiring stable component supply and long-term production continuity.

Supply support for INA199C1RSWT 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 leader specializing in analog and embedded processing technologies, with decades of expertise in precision signal conditioning and power management ICs.

The INA199 product line was designed specifically for high-accuracy, low-power current sensing in space- and energy-constrained applications - targeting notebook, wireless charging, telecom, and industrial power systems where shunt voltage headroom is limited.

FAQ

What is the maximum common-mode voltage supported by the INA199C1RSWT?

The INA199C1RSWT supports a common-mode input voltage range of –0.1 V to 26 V across its full operating temperature range of –40°C to +125°C. This specification applies specifically to the C-grade version (INA199Cx), enabling reliable high-side sensing on 24-V industrial buses and low-side sensing near ground without level-shifting circuitry. The –0.1 V lower limit permits slight negative transients during switching events.

Does the INA199C1RSWT require external gain-setting resistors?

No, the INA199C1RSWT does not require external gain-setting resistors. It integrates precision internal thin-film resistors (R1 = R2 = 1 MΩ, R3 = R4 = 10 kΩ) to deliver a fixed 100 V/V gain. This eliminates gain error from external resistor tolerances and layout parasitics, ensuring ±1% maximum gain error over temperature - a key advantage over discrete op-amp-based current-sense solutions.

How does the REF pin function in the INA199C1RSWT?

The REF pin in the INA199C1RSWT sets the output common-mode voltage, allowing the output to be level-shifted between 0 V and V+. When REF is tied to GND, the output swings from ~5 mV to (V+) – 50 mV; when REF = V+/2, the output centers at V+/2. This feature enables direct interfacing with differential-input ADCs or ratiometric single-ended ADCs without additional op-amps or level shifters - a capability not present in many competing current-sense amplifiers.

What is the thermal resistance of the INA199C1RSWT in its UQFN package?

The INA199C1RSWT in the RSW (10-pin UQFN) package has a junction-to-ambient thermal resistance (R_θJA) of 107.3°C/W and a junction-to-board thermal resistance (R_θJB) of 18.7°C/W. These values are measured under JEDEC JESD51-7 conditions with 2-layer board and 1-in² copper pad. The low R_θJB confirms efficient heat transfer to the PCB, supporting high-density layouts in thermally constrained wireless charging and telecom modules.

Can the INA199C1RSWT be used for bidirectional current sensing?

Yes, the INA199C1RSWT supports true bidirectional current sensing. Its differential input architecture accepts either polarity of shunt voltage: positive voltage on IN+ relative to IN– indicates current flow in one direction, while negative voltage indicates reverse flow. Combined with the REF pin's ability to set output baseline, this enables precise measurement of charge/discharge currents in battery management systems without polarity-switching circuitry.