Texas Instruments INA381A1IDGSR

Overview

INA381A1IDGSR from Texas Instruments is a 26-V, high-speed current-sense amplifier with integrated comparator, designed for overcurrent protection in high-side and low-side sensing configurations. It delivers 20 V/V gain, ±500 µV max offset at 12 V common-mode, 350 kHz bandwidth, and 400 ns comparator propagation delay. It operates from 2.7 V to 5.5 V supply and supports –0.2 V to +26 V input common-mode range - enabling use in merchant server PSUs and cordless power tools.

For engineers reviewing the INA381A1IDGSR datasheet, INA381A1IDGSR pinout, INA381A1IDGSR application, or INA381A1IDGSR equivalent, this page provides verified functional context, validated package mapping (VSSOP-10), confirmed pin roles, real-world timing performance (sub-10 µs total overcurrent response), and two technically documented alternative parts for system-level design trade-offs.

Technical Context

The INA381A1IDGSR implements a zero-drift amplifier topology with integrated open-drain comparator, supporting both transparent and latched alert modes via the RESET pin. Its input stage tolerates –0.2 V to +26 V common-mode voltage independent of its 2.7–5.5 V supply rail, enabling direct high-side bus monitoring without level-shifting circuitry.

It features 20 V/V fixed gain, 1 µV/°C max offset drift, and 1% max gain error at 25°C. The comparator includes 50 mV hysteresis and responds to overlimit conditions with <2 µs large-signal alert time, contributing to a total system overcurrent protection response under 10 µs.

Key Specifications

Pinout & Package

INA381A1IDGSR is housed in a 10-pin VSSOP package (3.00 mm × 3.00 mm body) with exposed thermal pad connected to GND. Pin 6 is NC (no internal connection) and may be left floating, grounded, or tied to VS+ per layout requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA381A2IDGSR and INA240A1D, the INA381A1IDGSR offers optimal balance of gain accuracy (±1% at 25°C), integrated alert logic, and compact VSSOP-10 footprint - making it preferred for cost-sensitive, space-constrained 12–24 V industrial and consumer power systems requiring self-contained overcurrent response.

Availability

INA381A1IDGSR is available at Aetrix Electronics and suitable for merchant server PSUs, cordless power tools, and industrial DC/DC converters requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for INA381A1IDGSR 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 analog signal chain products.

The INA381 product line targets high-speed, high-accuracy current sensing for overcurrent protection in power conversion and motor control systems - emphasizing integration, speed, and robustness across extended temperature ranges.

FAQ

What is the maximum common-mode voltage the INA381A1IDGSR can handle?

The INA381A1IDGSR supports a common-mode input voltage range of –0.2 V to +26 V, independent of its 2.7–5.5 V supply voltage. This allows direct high-side sensing on 24 V bus rails without level-shifting circuitry. The device remains undamaged even when 26 V is applied to IN+ and IN− with VS+ disconnected, per absolute maximum ratings.

Does the INA381A1IDGSR require external components to operate as a complete overcurrent detector?

The INA381A1IDGSR requires only an external 10 kΩ pull-up resistor on the ALERT pin and a reference voltage source (e.g., resistor divider or REF3140) on CMPREF to function as a complete overcurrent detector. No external op-amp, comparator, or hysteresis network is needed - all core functions are integrated into the single INA381A1IDGSR die.

How does the RESET pin affect the behavior of the ALERT output on the INA381A1IDGSR?

The RESET pin configures the ALERT output mode: when held high, the INA381A1IDGSR operates in transparent mode (ALERT follows input state in real time); when pulled low, it enters latched mode (ALERT stays asserted until RESET is toggled high). This dual-mode flexibility enables both instantaneous fault reporting and persistent fault flagging in safety-critical systems.

Can the INA381A1IDGSR be used with a 3.3 V supply while monitoring a 24 V bus?

Yes - the INA381A1IDGSR operates from 2.7 V to 5.5 V supply and tolerates –0.2 V to +26 V common-mode voltage on IN+ and IN− simultaneously. With a 3.3 V VS+, it accurately amplifies shunt voltage differentials on a 24 V bus, outputs VOUT referenced to its own supply, and asserts ALERT using its open-drain structure compatible with 3.3 V or 5 V pull-up rails.

What is the total overcurrent response time of the INA381A1IDGSR, and what contributes to it?

The total system overcurrent protection response time of the INA381A1IDGSR is less than 10 µs. This includes amplifier small-signal propagation delay, comparator propagation delay (400 ns typ), and output driver rise/fall time. The integrated architecture eliminates inter-stage delays present in discrete amplifier + comparator designs, delivering faster end-to-end fault detection than modular alternatives.