Texas Instruments INA219AID

Overview

INA219AID from Texas Instruments is a zero-drift, bidirectional current/power monitor IC with I²C/SMBus interface, measuring shunt voltage (±320 mV full-scale), bus voltage (0–26 V), and computing real-time power (watts). It operates from 3–5.5 V supply, draws ≤1 mA quiescent current, and supports industrial temperature range (–40°C to +125°C) - used in server power rail monitoring and telecom DC-DC output supervision.

For engineers reviewing the INA219AID datasheet, INA219AID pinout, INA219AID application, or INA219AID equivalent, key selection considerations include its 12-bit delta-sigma ADC with programmable PGA (/1–/8), dual independent averaging for shunt/bus channels, 16 I²C addresses, ±0.5% current measurement error over temperature, and SOT23-8 package compatibility with high-density PCB layouts.

Technical Context

The INA219AID integrates a precision delta-sigma ADC with internal programmable gain amplifier (PGA) and dedicated bus voltage channel, enabling simultaneous high-resolution shunt voltage (10 µV LSB) and bus voltage (4 mV LSB) digitization. Its architecture supports independent configuration of conversion time (9–12 bit), sample averaging (1–1024), and full-scale ranges (shunt: 40/80/160/320 mV; bus: 16/32 V).

It implements on-chip multiplication logic to derive current (amperes) and power (watts) registers from calibrated shunt and bus measurements, eliminating host MCU computation overhead. The device features automatic conversion sequencing, conversion-ready flag (CNVR), and Power-Down mode with 40 µs wake-up - all controlled via I²C register map without external components.

Key Specifications

Pinout & Package

SOT-23-8 package (1.63 mm × 2.90 mm), thermally enhanced for compact power monitoring designs; pin-compatible with SOIC-8 variant but optimized for space-constrained layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current/power monitoring applications.

Compared with INA226AIDGST and MAX4008AUB+, the INA219AID delivers optimal integration for space-constrained, cost-sensitive power monitoring - combining calibrated digital output, I²C interface, and SOT23-8 footprint without external support components.

Availability

INA219AID is available at Aetrix Electronics and suitable for server power rail monitoring, telecom DC-DC supervision, and notebook battery charge path applications requiring stable component supply and long-term production continuity.

Supply support for INA219AID 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 chain and power management solutions.

The INA219AID belongs to TI's high-accuracy current sense amplifier product line, designed specifically for digital power monitoring in servers, telecom infrastructure, and portable electronics where compact size, I²C simplicity, and calibrated output are critical.

FAQ

What is the maximum bus voltage the INA219AID can measure?

The INA219AID supports a bus voltage input range of 0 V to 26 V, referenced to the IN− pin. This allows direct measurement of common intermediate bus voltages including 12 V, 24 V, and 48 V systems without external level-shifting circuitry. The device's absolute maximum rating for common-mode voltage is 26 V, and exceeding this may cause permanent damage. Always ensure VIN+ and VIN− remain within –0.3 V to 26 V relative to GND.

Does the INA219AID require external calibration components?

No, the INA219AID does not require external calibration components. It uses an internal programmable calibration register (05h) that the user configures once based on shunt resistance and expected full-scale current. After programming, the INA219AID automatically computes current (A) and power (W) values in its output registers. The calibration process is software-defined and eliminates trimming resistors or EEPROM-based compensation.

How does the PGA setting affect shunt voltage measurement on the INA219AID?

The PGA setting on the INA219AID scales the full-scale shunt voltage range: /1 = ±40 mV, /2 = ±80 mV, /4 = ±160 mV, /8 = ±320 mV. Higher PGA gains reduce effective resolution (larger µV/LSB) but increase measurable current range for a given shunt resistor. For example, with a 10 mΩ shunt, /1 supports up to 4 A, while /8 supports up to 32 A - enabling flexible trade-offs between sensitivity and dynamic range.

Can the INA219AID operate from a 3.3 V supply while monitoring a 24 V bus?

Yes, the INA219AID can operate from a 3.3 V supply (within its 3–5.5 V range) while monitoring a 24 V bus. Its IN+ and IN− pins tolerate up to 26 V common-mode voltage, and the VS supply is fully isolated from the bus voltage domain. No level-shifting or isolation is needed between the 3.3 V logic domain and the 24 V measurement domain, simplifying system architecture and reducing BOM count.

What is the function of the CNVR bit in the Status register of the INA219AID?

The CNVR (Conversion Ready) bit in the INA219AID Status register (bit 2 of register 01h) indicates completion of all conversions, averaging, and multiplication operations required to update the Current, Bus Voltage, and Power registers. It is set automatically after each full measurement cycle and cleared upon reading the Status register, writing to the Configuration register (except Power-Down/ADC Off), or triggering a new conversion - enabling reliable synchronization in interrupt-driven firmware.