INA226 power monitor: specs and pinout
A module built around the Texas Instruments INA226, a 16-bit I2C current, bus voltage and power monitor with an alert pin. This page gives the INA226 chip facts; the module's shunt resistor value, pull-ups and header order are not covered by an official document.
Specs
| Spec | Value | Source |
|---|---|---|
| Bus voltage input range | 0 V to 36 V (do not apply more than 36 V) | source Section 5.5 Electrical Characteristics, p.5 and note (1) p.6 |
| Supply voltage | 2.7 V to 5.5 V; absolute maximum 6 V | source Features p.1; Section 5.1 p.4; Section 5.5 p.6 |
| Supply current | 330 uA typ, 420 uA max; shutdown 0.5 uA typ, 2 uA max | source Section 5.5 Power Supply, p.6 |
| Shunt voltage measurement | Input range about -81.9 mV to +81.92 mV; 1 LSB = 2.5 uV; 16-bit ADC | source Section 5.5, p.5 |
| Bus voltage resolution | 1 LSB = 1.25 mV | source Section 5.5, p.5 |
| Accuracy | Gain error 0.1% max (shunt and bus); shunt offset 10 uV max | source Features p.1; Section 5.5, p.5 |
| Interface | I2C / SMBus compatible; 16 programmable addresses via pins A0 and A1; A1 and A0 both to GND gives 1000000 (0x40) | source Section 6.5 Table 6-2 |
| Digital input low level | VIL max 0.3 x VS | source Section 5.5 p.6 |
| Common-mode input (IN+, IN-) | Absolute maximum -0.3 V to 40 V | source Section 5.1, p.4 |
| Operating temperature | -40 C to +125 C | source Section 5.3, p.4 |
Power
| Value | Source | |
|---|---|---|
| Supply | VS 2.7 V to 5.5 V (chip) | source Section 5.5, p.6 |
| Current | 330 uA typ (chip only) | source Section 5.5, p.6 |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
The module board (shunt resistor value, I2C pull-ups, header order, address solder pads) is not covered by an official document; pin rows above are the INA226 chip's 10-pin VSSOP pins.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| A1 (pin 1) | Address pin | Connect to GND, SCL, SDA or VS | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| A0 (pin 2) | Address pin | Connect to GND, SCL, SDA or VS | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| Alert (pin 3) | Alert output | Multi-functional, open-drain | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| SDA (pin 4) | I2C data | Open-drain input/output | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| SCL (pin 5) | I2C clock | Open-drain input | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| VS (pin 6) | Power supply | 2.7 V to 5.5 V | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| GND (pin 7) | Ground | 0 V | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| VBUS (pin 8) | Bus voltage input | 0 V to 36 V | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| IN- (pin 9) | Shunt negative input | Connect to load side of shunt | source Section 4, Table 4-1 and Figure 4-1 (p.3) | |
| IN+ (pin 10) | Shunt positive input | Connect to supply side of shunt | source Section 4, Table 4-1 and Figure 4-1 (p.3) |
Build with it
Project ideas for the INA226 power monitor. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Battery power logger: A single cell is well inside the 36 V bus range, and the ESP32's 3.3 V I2C matches a 3.3 V INA226 supply. Check the module's shunt value for the current range. Learning project.
- Solar panel output monitor: Reads the panel on the high side of the load; the voltage is within the 36 V limit. Learning project in logging real panel output over a day.
- Standby current meter for a 3.3 V board: Put the INA226 shunt in series between the regulator and the load. The regulator sheet rates 1 A output; the shunt's range is set by its value. Learning project.
Common mistakes
- Full-scale shunt voltage is only about 82 mV, so the measurable current is that voltage divided by the module's shunt resistor, whose value is not documented here; check the marking on the shunt before setting the calibration (source: link, Section 5.5).
- VS is the chip's own supply and must stay within 2.7 V to 5.5 V (6 V absolute max); the 0 V to 36 V range is the measured bus, not the supply (source: link, Sections 5.1 and 5.5).
- IN+ connects to the supply side and IN- to the load side of the shunt; reversing them reads negative, and both pins must stay within -0.3 V to 40 V (source: link, Table 4-1 and Section 5.1).
Not covered by the official source
- Module shunt resistor value and pull-up arrangement are not documented, so no current range or module logic-level statement is made.
- The revision line on the PDF reads 'Revised August 2026' (SBOS547C); I2C clock limits are not given here.
Sources
- link (TI INA226 data sheet SBOS547C)