Texas Instruments INA199A1RSWR

Overview

INA199A1RSWR 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, 50 V/V fixed gain, –0.3 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 battery management and Qi wireless charging transmitters.

For engineers reviewing the INA199A1RSWR datasheet, INA199A1RSWR pinout, INA199A1RSWR application, or INA199A1RSWR equivalent, this page delivers verified technical context, package-specific pin functions, real-world use-value mapping, and validated alternative options - all grounded in TI's SBOS469H production data sheet and RSW package documentation.

Technical Context

The INA199A1RSWR implements a zero-drift chopper-stabilized amplifier architecture to achieve <0.5 μV/°C offset drift and 10 ppm/°C gain drift over –40°C to +125°C. Its differential input stage rejects common-mode voltages up to 26 V independent of supply, enabling direct sensing on 12-V or 24-V rails while powered from as low as 2.7 V.

It uses internal precision resistor networks (R1 = R2 = 1 MΩ, R3 = R4 = 20 kΩ) to fix gain at 50 V/V, eliminating external gain-setting components. The RSW (10-pin UQFN) package provides dual IN+ and dual IN– pins - internally tied - to reduce layout-induced mismatch and improve high-frequency CMRR stability.

Key Specifications

Pinout & Package

The INA199A1RSWR 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 compact PCB layouts with minimal heatsinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA199A1RSWR, INA219AIDR trades analog simplicity for digital configurability and multi-function integration, while MAX4080TASA+ extends voltage range at the cost of offset stability and package size - making INA199A1RSWR optimal for compact, precision, analog-coupled 26-V sensing.

Availability

INA199A1RSWR is available at Aetrix Electronics and suitable for notebook computers, Qi-compliant wireless charging transmitters, and telecom equipment requiring stable component supply, consistent parametric performance, and long-lifecycle availability.

Supply support for INA199A1RSWR 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 focused on analog and embedded processing technologies, with decades of expertise in precision signal conditioning and power management ICs.

The INA199 family was designed specifically for high-accuracy, low-power current sensing in space-constrained, thermally demanding applications - emphasizing zero-drift stability, wide common-mode operation, and minimal external component count.

FAQ

What is the maximum common-mode voltage the INA199A1RSWR can handle?

The INA199A1RSWR supports a common-mode input voltage range of –0.3 V to 26 V across its full operating temperature range of –40°C to +125°C. This specification applies specifically to the INA199A version per TI's SBOS469H datasheet Section 6.5. It enables reliable high-side sensing on 24-V rails and low-side sensing below ground in bidirectional battery applications - all while powered from a 3.3-V supply. The 26-V limit is absolute; exceeding it risks permanent damage.

Does the INA199A1RSWR require external gain-setting resistors?

No, the INA199A1RSWR does not require external gain-setting resistors. It integrates precision internal resistors (R1 = R2 = 1 MΩ, R3 = R4 = 20 kΩ) to deliver a fixed 50 V/V gain. This eliminates resistor matching errors, board space, and thermal drift contributions from external components - a key design advantage confirmed in TI's Device Comparison Table and Section 7.3.2. The gain is factory-trimmed and invariant across temperature and supply voltage.

How does the dual IN+ and dual IN− pin configuration benefit layout?

The INA199A1RSWR's dual IN+ (pins 2 & 3) and dual IN− (pins 4 & 5) in the RSW package are internally tied and intended to reduce PCB trace-length mismatch. This symmetry minimizes parasitic inductance and capacitance imbalance between inputs, preserving common-mode rejection ratio (CMRR) above 100 dB at DC and improving high-frequency stability - especially critical in noisy switch-mode power supply environments. TI explicitly recommends tying them together in Section 7.3.1.

Can the INA199A1RSWR be used for bidirectional current sensing?

Yes, the INA199A1RSWR supports true bidirectional current sensing. Its –0.3 V to 26 V common-mode input range allows the IN– pin to be biased below GND (e.g., –0.1 V), enabling detection of reverse current flow through the shunt. When REF is set to mid-supply (e.g., V+/2), the output swings symmetrically above and below that reference - delivering positive voltage for forward current and negative voltage for reverse current. This behavior is documented in TI's Functional Block Diagram and Typical Applications section.

What is the purpose of the NC pins on the INA199A1RSWR RSW package?

The two NC (no-connect) pins on the INA199A1RSWR RSW package (pins 1 and 7) have no internal electrical connection. Per TI's Pin Functions table (Section 5), they may be left floating or connected to GND for mechanical stability and improved thermal conduction to the PCB. They serve no signal or power function - their inclusion aids manufacturability and thermal relief in the 1.80 mm × 1.40 mm UQFN footprint, but do not affect electrical performance of the INA199A1RSWR.