Texas Instruments INA381A3IDSGT

Overview

INA381A3IDSGT from Texas Instruments is a 26-V, high-speed current-sense amplifier with integrated comparator and fixed gain of 100 V/V, designed for overcurrent protection in high-side and low-side sensing applications. It operates from 2.7 V to 5.5 V supply, supports –0.2 V to +26 V common-mode input range, delivers ≤1% gain error at 25°C, and achieves <10 µs total system overcurrent response time. It is used in merchant DC/DC supplies and cordless power tools for real-time load monitoring and fault shutdown.

For engineers reviewing the INA381A3IDSGT datasheet, INA381A3IDSGT pinout, INA381A3IDSGT application, or INA381A3IDSGT equivalent, this page provides verified functional context, validated package mapping (WSON-8), confirmed pin roles, exact gain-specific electrical behavior (G = 100), and two technically documented alternative parts with explicit differences in gain, bandwidth, and comparator hysteresis.

Technical Context

The INA381A3IDSGT implements a zero-drift topology enabling ≤150 µV max offset at 0 V common-mode and 1 µV/°C drift over –40°C to +125°C. Its amplifier stage provides 150 kHz small-signal bandwidth and 2 V/µs slew rate, while the open-drain comparator features 400 ns propagation delay (typ), 50 mV hysteresis, and user-configurable transparent/latched alert modes via RESET pin.

It accepts differential inputs across IN+ and IN–, references CMPREF for threshold comparison, outputs amplified sense voltage on VOUT, and asserts active-low ALERT when VOUT exceeds CMPREF by >50 mV. The device withstands 26 V common-mode at pins even with VS removed, and draws ≤350 µA quiescent current.

Key Specifications

Pinout & Package

INA381A3IDSGT is packaged in an 8-pin WSON (DSG) with 2.00 mm × 2.00 mm body size and exposed thermal pad tied to GND. Pin 1 is marked by dot; thermal pad must be soldered to PCB ground plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA381A2IDSGT and INA301A3IDSGR, the INA381A3IDSGT uniquely integrates comparator functionality with 100× gain and 150 kHz bandwidth in a single WSON-8 package-reducing BOM count and PCB area while maintaining sub-10 µs system-level fault response.

Availability

INA381A3IDSGT is available at Aetrix Electronics and suitable for merchant DC/DC supplies, cordless power tools, and DC-input BLDC motor drives requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for INA381A3IDSGT 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 amplifiers, power management, and signal chain solutions.

The INA381 product line delivers integrated current-sense amplifiers with onboard comparators for high-reliability overcurrent protection in power conversion, motor control, and battery management systems.

FAQ

What is the gain setting of the INA381A3IDSGT?

The INA381A3IDSGT has a fixed gain of 100 V/V, as indicated by the "A3" suffix in the part number. This gain is laser-trimmed during manufacturing and cannot be adjusted externally. It scales the differential input voltage across IN+ and IN– by exactly 100× to produce the VOUT signal, enabling precise current measurement with shunt resistors as low as 1 mΩ while maintaining signal integrity and minimizing power loss in the INA381A3IDSGT application circuit.

Does the INA381A3IDSGT support high-side current sensing?

Yes, the INA381A3IDSGT supports high-side current sensing with a common-mode input range of –0.2 V to +26 V, fully independent of its 2.7 V to 5.5 V supply voltage. This allows direct connection to 12 V or 24 V bus rails without level-shifting circuitry. The device remains functional and undamaged even when VS is unpowered but 26 V is present on IN+ and IN–, making it robust for high-side monitoring in INA381A3IDSGT-based power supply designs.

How does the ALERT output behave in latched mode?

In latched mode, the ALERT output of the INA381A3IDSGT remains asserted (low) after an overcurrent event until the RESET pin receives a low-to-high transition. This behavior is enabled by pulling RESET high (e.g., to VS). Latched mode ensures fault persistence for system-level diagnostics and safe shutdown sequencing. The INA381A3IDSGT's internal latch holds state even if the overcurrent condition clears, providing reliable fault capture for microcontrollers reading the ALERT signal.

What is the maximum recommended capacitive load on the VOUT pin of the INA381A3IDSGT?

The INA381A3IDSGT supports a maximum capacitive load of 1 nF on the VOUT pin without sustained oscillation, as specified in the Electrical Characteristics table. Driving larger capacitances-such as ADC input filters or long PCB traces-may degrade stability and step response. For such cases, a series resistor (e.g., 10 Ω) between VOUT and the capacitive load is recommended to maintain phase margin. This limit applies directly to the INA381A3IDSGT and is verified across temperature and supply conditions.

Can the INA381A3IDSGT operate with a 3.3 V supply?

Yes, the INA381A3IDSGT operates fully across 2.7 V to 5.5 V supply voltage, including 3.3 V nominal systems. At 3.3 V, VOUT swings within 50 mV of the rails (i.e., 0.05 V to 3.25 V), and the comparator ALERT output remains compatible with 3.3 V logic thresholds. Quiescent current stays ≤350 µA, and all key specs-including offset, gain error, and bandwidth-are guaranteed over this range. This makes the INA381A3IDSGT suitable for 3.3 V microcontroller-based monitoring in INA381A3IDSGT implementations.