Texas Instruments INA303A3IPW

Overview

INA303A3IPW from Texas Instruments is a 36-V, precision bidirectional current-sense amplifier with integrated window comparator functionality, designed for high-accuracy overcurrent and undercurrent detection in power rails up to +36 V common-mode. It features 100 V/V gain, ±30 µV max offset voltage (A3 grade), 0.5 µV/°C max drift, and dual open-drain alert outputs - ALERT1 (sub-1 µs response) and ALERT2 (adjustable 2 µs–10 s delay) - used in motor phase protection and DC-DC converter output monitoring.

For engineers reviewing the INA303A3IPW datasheet, INA303A3IPW pinout, INA303A3IPW application, or INA303A3IPW equivalent, this device delivers verified window-comparator behavior, TSSOP-14 package compatibility, rail-to-rail output swing, and guaranteed operation from –40°C to +125°C - critical for industrial motor drives and telecom power systems requiring fast, accurate fault detection without external comparators.

Technical Context

The INA303A3IPW implements a zero-drift chopper-stabilized amplifier core enabling ±30 µV max input offset and 0.5 µV/°C max drift across –40°C to +125°C, supporting precise low-value shunt measurements. Its dual comparators are configured as a window detector: COMP1 triggers on overcurrent (exceeding LIMIT1 threshold), COMP2 triggers on undercurrent (falling below LIMIT2 threshold), both referenced to the REF pin voltage.

Thresholds are set via external resistors connected to LIMIT1 and LIMIT2 pins, each sourcing a precision 80 µA current (±1.6 µA over temperature). ALERT2 delay is programmable using an external capacitor on the DELAY pin, with timing governed by a 5 µA internal current source and 1.22 V threshold - enabling configurable response windows from microseconds to seconds.

Key Specifications

Pinout & Package

INA303A3IPW is housed in a 14-pin TSSOP (PW) package measuring 4.40 mm × 5.00 mm, with exposed thermal pad for enhanced power dissipation in continuous high-current monitoring applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA302A3IPW and INA240A3IPW, the INA303A3IPW uniquely integrates window-comparator logic with programmable delay in a single 14-pin TSSOP, reducing PCB area and component count for applications requiring coordinated over/undercurrent response - especially where space and fault-handling sophistication are constrained.

Availability

INA303A3IPW is available at Aetrix Electronics and suitable for motor control, telecom rectifier supervision, and industrial PLC I/O protection requiring stable component supply, extended temperature qualification, and guaranteed long-term availability.

Supply support for INA303A3IPW 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 INA30x product line was engineered specifically for high-reliability current monitoring in industrial, automotive, and telecom power systems - combining zero-drift amplification, robust common-mode tolerance, and integrated fault-detection logic to replace multi-component discrete solutions.

FAQ

What is the key functional difference between INA303A3IPW and INA302A3IPW?

The INA303A3IPW implements a window comparator configuration: ALERT1 triggers on overcurrent (exceeding LIMIT1), ALERT2 triggers on undercurrent (falling below LIMIT2). In contrast, the INA302A3IPW configures both comparators for independent overcurrent detection only. This makes the INA303A3IPW essential for applications requiring coordinated high/low fault boundaries - such as motor stall detection or DC-DC converter undervoltage lockout - where the INA302A3IPW cannot substitute without redesign.

How is the ALERT2 delay time calculated for INA303A3IPW?

The ALERT2 delay time for INA303A3IPW is determined by the external capacitor CDELAY connected to the DELAY pin, using the formula t = (CDELAY × 1.22 V) / 5 µA. The DELAY pin sources a precision 5 µA current into CDELAY until it reaches the 1.22 V threshold, at which point ALERT2 activates. For example, a 100 pF capacitor yields ~24.4 µs delay; a 10 µF capacitor yields ~2.44 s - covering the full 2 µs to 10 s range specified in the datasheet.

Can INA303A3IPW operate with a 24 V common-mode voltage while powered from 3.3 V?

Yes. The INA303A3IPW supports a common-mode input range of –0.1 V to +36 V independent of its 2.7–5.5 V supply voltage (VS). When monitoring a 24 V rail, IN+ and IN– can sit at 24 V and 23.99 V respectively, while VS remains at 3.3 V - enabling high-side sensing without level-shifting circuitry. This is confirmed in Section 6.3 (Recommended Operating Conditions) and Figure 17 of the SBOS775C datasheet.

What is the purpose of the REF pin in INA303A3IPW, and how should it be configured?

The REF pin sets the output voltage midpoint for bidirectional current sensing. With REF tied to VS/2 (e.g., 1.65 V for 3.3 V supply), OUT swings symmetrically above/below that voltage - +2.5 V for positive current, –2.5 V for negative current (scaled by gain). This enables true bidirectional measurement using a single-supply amplifier. REF must be driven by a low-impedance source; a simple resistor divider from VS is sufficient for most applications, as shown in Figure 41 of the datasheet.

Does INA303A3IPW require external components for basic operation, and which ones are mandatory?

Yes. Mandatory external components for INA303A3IPW include: (1) CBYPASS (0.1 µF ceramic capacitor from VS to GND), (2) RPULL-UP (10 kΩ resistor from ALERT1/ALERT2 to logic supply), and (3) RLIMIT1/RLIMIT2 (resistors setting LIMIT1/LIMIT2 thresholds). Optional but recommended: CDELAY for ALERT2 timing and RSENSE (shunt resistor). No external op-amps, comparators, or DACs are needed - all signal conditioning and decision logic is integrated.