Overview
The INA228AIDGST from Texas Instruments is an ultra-precise digital power monitor designed for high-accuracy current-sensing applications. It features a 20-bit delta-sigma ADC and is capable of measuring current, bus voltage, temperature, power, energy, and charge accumulation. The device operates over a wide common-mode range of –0.3 V to +85 V and supports bus voltage sensing from 0 V to 85 V. Its high-resolution ADC and low offset and gain drift make it suitable for precise systems without the need for multi-temperature calibration during manufacturing.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| ADC Resolution | 20-bit | |
| Offset Voltage | ±1 µV (maximum) | µV |
| Offset Drift | ±0.01 µV/°C (maximum) | µV/°C |
| Gain Error | ±0.05% (maximum) | % |
| Gain Error Drift | ±20 ppm/°C (maximum) | ppm/°C |
| Common Mode Rejection | 154 dB (minimum) | dB |
| Power Monitoring Accuracy | 0.5% full scale, –40°C to +125°C (maximum) | % |
| Energy and Charge Accuracy | 1.0% full scale (maximum) | % |
| Alert Response Time | 75 µs | µs |
| Shunt Full-Scale Differential Range | ±163.84 mV / ±40.96 mV | mV |
| Input Bias Current | 2.5 nA (maximum) | nA |
| Temperature Sensor Accuracy | ±1°C (maximum at 25°C) | °C |
| Supply Voltage | 2.7 V to 5.5 V | V |
| Operational Current | 640 µA (typical) | µA |
| Shutdown Current | 5 µA (maximum) | µA |
| I2C Interface Speed | 2.94 MHz | MHz |
| I2C Addresses | 16 pin-selectable addresses |
Key Features
- High-resolution, 20-bit delta-sigma ADC for precise measurements.
- Low offset voltage (±1 µV maximum) and low gain drift (±0.01 µV/°C maximum) for accurate current sensing.
- Wide common-mode range of –0.3 V to +85 V and bus voltage sense input from 0 V to 85 V.
- Fast alert response time of 75 µs.
- Programmable conversion time (50 µs to 4.12 ms) and sample averaging (1x to 1024x) to reduce noise.
- Integrated temperature sensor with ±1°C accuracy at 25°C.
- Programmable resistor temperature compensation.
- High-speed I2C interface with 16 pin-selectable addresses.
- Low input bias current (2.5 nA maximum) allowing for larger current-sense resistors.
Applications
- DC/DC converters and power inverters.
- Industrial battery packs.
- Power-over-ethernet (PoE) systems.
- Telecom equipment.
- Enterprise servers.
Q & A
- What is the resolution of the ADC in the INA228?
The INA228 features a high-resolution 20-bit delta-sigma ADC. - What is the offset voltage of the INA228?
The offset voltage is ±1 µV (maximum). - What is the common-mode range of the INA228?
The common-mode range is –0.3 V to +85 V. - How fast is the alert response time of the INA228?
The alert response time is 75 µs. - What is the range of the supply voltage for the INA228?
The supply voltage range is 2.7 V to 5.5 V. - What is the typical operational current of the INA228?
The typical operational current is 640 µA. - How many I2C addresses are selectable on the INA228?
There are 16 pin-selectable I2C addresses. - What is the accuracy of the integrated temperature sensor?
The temperature sensor is accurate to ±1°C at 25°C. - Can the conversion time and averaging be programmed on the INA228?
Yes, the conversion time can be set from 50 µs to 4.12 ms, and sample averaging can be set from 1x to 1024x. - What are some typical applications of the INA228?
The INA228 is used in DC/DC converters, industrial battery packs, Power-over-ethernet (PoE) systems, telecom equipment, and enterprise servers.
