Current Sensors

INA226AIDGSR

INA226AIDGSR - 16-Bit I2C Current/Power Monitor | TI

The Texas Instruments INA226AIDGSR is a 36 V, 16-bit, ultra-precise I2C output current, voltage, and power monitor with alert function. It is offered in a 10-VSSOP (DGS) surface-mount package and is specified for -40°C to +125°C operation. The device supports both high-side and low-side shunt measurements, and its bidirectional current sensing allows charge/discharge monitoring in battery or power-supply systems. A current shunt monitor (also called a current/power monitor) is an analog-front-end IC that measures the voltage drop across a low-value external sense resistor and, together with the bus voltage, computes current and power. The INA226 digitizes this information with a 16-bit delta-sigma ADC and outputs directly readable current and power values over I2C or SMBus, eliminating the need for a discrete amplifier plus ADC. In a system hierarchy, the INA226 sits between the power stage and the host controller: it senses the rail, reports data over a digital bus, and can assert an alert pin for overcurrent or undercurrent conditions. Key features include a 36 V bus-voltage rating, 16-bit measurement resolution, programmable calibration, conversion times, and averaging, plus an integrated multiplier for direct amperes/watts readout. The I2C/SMBus interface supports multiple device addresses, and the alert pin can be programmed to respond to shunt voltage, bus voltage, or power limits. According to TI, the INA226 is designed for high-side or low-side, bidirectional measurement, which makes it suitable for precision power monitoring. From a design perspective, the INA226 uses an external shunt resistor and measures the shunt voltage differentially across IN+ and IN-. The bus voltage is measured separately at the VIN pin. The internal ADC and digital engine perform the multiplication, while the calibration register scales the result to the actual shunt value. The device also offers programmable conversion time and averaging, allowing designers to trade speed versus noise for different system requirements. Typical applications include server and datacenter power monitoring, battery charging and discharging in portable equipment, industrial automation power rails, telecom/networking equipment, solar inverters, and test-and-measurement instrumentation. The wide common-mode range and I2C output simplify integration with microcontrollers and BMS controllers. When designing with the INA226, place the shunt resistor close to the sense pins and use Kelvin-connected traces to minimize parasitic resistance. Ensure I2C pull-up resistors are sized correctly and the alert pin is configured with an appropriate limiting register before enabling interrupts.