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Texas Instruments · Integrated circuit

INA219 Current and Power Monitor

Measures current and voltage on a rail up to 26 V and reports both over I2C, while running from 3.3 V itself. The part behind most USB power meters.

Cheat sheet (SVG)
Logic level
3-5.5 V supply, senses up to 26 V
Package
SOIC-8 (D) shown; SOT-23-8 (DCN) differs

1.Pinout diagram

Highlight a signalhover to preview, click to keep

Pins 1-4

INA219

Pins 5-8

Pin detail

Hover a pin for its mappings and gotchas. Click to keep it here.

Logic level
3-5.5 V supply, senses up to 26 V
Package
SOIC-8 (D) shown; SOT-23-8 (DCN) differs

Fig. 1. INA219 Current and Power Monitor, SOIC-8 (D) shown; SOT-23-8 (DCN) differs. Hover or tap a signal to light up every pin that carries it.

2.Watch out

  • The two packages are not the same pinout. This diagram is the SOIC-8. On the SOT-23-8 the order is 1 IN+, 2 IN-, 3 GND, 4 VS, 5 SCL, 6 SDA, 7 A0, 8 A1, which is close to reversed. Check which package you have before probing.
  • It is a high-side sensor: IN+ and IN- sit at up to 26 V common mode while the chip itself runs from 3 to 5.5 V. That is the whole point of the part, and it is why the shunt goes in the positive rail rather than the ground return.
  • The current and power registers read zero until you write the calibration register. Nothing is broken, and the shunt and bus voltage registers work the whole time, which is what makes this confusing. Calibration is also what sets the current LSB.
  • Full-scale shunt voltage is +/-40 mV with the PGA at /1 and +/-320 mV at /8. Bus voltage has two ranges, 16 V and 32 V. Picking the smallest range that fits buys you resolution.
  • A0 and A1 each go to GND, VS, SDA or SCL, not just to a rail, which is how eight address pins' worth of range comes out of two: 16 addresses, 0x40 to 0x4F.
  • Breakout boards almost always carry a 0.1 ohm shunt, which hits full scale at 3.2 A. For more current you replace the resistor and recalculate, and for much less you want a larger one or the shunt voltage disappears into the noise.
  • The INA226 is the same idea with 16-bit resolution and an alert pin. Not a drop-in: different pinout and a different register map.

3.Minimum high-side sensing circuit

What has to go around the chip before it will run.

VCCGNDINA2190.1 uF ceramic between VS (5) and GND0.1 uFceramic4.7 kOhm between SDA (3) and VCC4.7 kOhm4.7 kOhm between SCL (4) and VCC4.7 kOhmAddress link between A1 (1) and GNDAddresslinkAddress link between A0 (2) and GNDAddresslinkVS (5) to VCCGND (6) to GND0.1 ohm 1% shunt between IN+ (8) and IN- (7)0.1 ohm 1% shuntA1 1A0 2SDA 3SCL 4VS 5VS 5GND 6IN- 7IN+ 8
Fig. 2. Minimum high-side sensing circuit, drawn from Table 1. Crossing wires are not connected.
Table 1. External parts, and why each one is there.
PartBetween
0.1 ohm 1% shuntIN+ (8) to IN- (7)
0.1 uF ceramicVS (5) to GND
4.7 kOhmSDA (3) to VCC
4.7 kOhmSCL (4) to VCC
Address linkA1 (1) to GND
Address linkA0 (2) to GND

The shunt goes in the positive rail between the supply and the load, with IN+ toward the supply. Bus voltage is measured from IN- to ground, so IN- is the load side.

4.Full pin reference

Every pin, alias and mapping. This is the table that prints.

Table 2. Pin assignments.

Complete pin reference for INA219 Current and Power Monitor
PinNameFunctions

Primary sources

Found a wrong pin? The whole board is one file, data/boards/ina219.json.

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