Monitors current and bus voltage on three separate rails over I2C, each through its own external shunt, so one chip watches a whole supply tree. It reports shunt and bus voltage per channel from 0 to 26 V, and two open-drain alerts (warning and critical) trip against per-channel limits without host polling. Address pins allow several devices on one bus. A three-rail extension of the INA219 idea for multi-supply boards.

Pinout

Pin	Name	Type	Function
1	IN-3	input	Analog input. Connect to load side of the channel 3 shunt resistor. Bus voltage is the measurement from this pin to ground. Common-mode range 0V to 26V.
2	IN+3	input	Analog input. Connect to supply side of the channel 3 shunt resistor. Common-mode range 0V to 26V.
3	GND	power_in	Analog ground reference for the device.
4	VS	power_in	Power supply, 2.7V to 5.5V. Bypass to GND with a 0.1µF ceramic capacitor.
5	A0	input	Digital input. I2C/SMBus address select pin. Connect to GND, SCL, SDA, or VS to select one of four programmable device addresses (see Table 7-1).
6	SCL	input	I2C/SMBus serial clock line. Open-drain input; requires an external pull-up resistor (typ 10kΩ).
7	SDA	bidirectional	I2C/SMBus serial data line. Open-drain input/output; requires an external pull-up resistor (typ 10kΩ).
8	Warning	output	Averaged measurement warning alert. Open-drain digital output; requires an external pull-up resistor to VPU.
9	Critical	output	Conversion-triggered critical alert. Open-drain digital output; requires an external pull-up resistor to VPU.
10	PV	output	Power valid alert. Open-drain digital output; requires an external pull-up resistor to VPU.
11	IN-1	input	Analog input. Connect to load side of the channel 1 shunt resistor. Bus voltage is the measurement from this pin to ground. Common-mode range 0V to 26V.
12	IN+1	input	Analog input. Connect to supply side of the channel 1 shunt resistor. Common-mode range 0V to 26V.
13	TC	output	Timing control alert. Open-drain digital output; abs-max 26V.
14	IN-2	input	Analog input. Connect to load side of the channel 2 shunt resistor. Bus voltage is the measurement from this pin to ground. Common-mode range 0V to 26V.
15	IN+2	input	Analog input. Connect to supply side of the channel 2 shunt resistor. Common-mode range 0V to 26V.
16	VPU	power_in	Pull-up supply voltage used to bias the power valid (PV) output circuitry and typically the alert open-drain pull-ups.
17	Thermal Pad	passive	Exposed thermal pad on package bottom. Must be connected to ground or left floating.

Key specifications

Parameter	Value
Type	3-channel current / bus-voltage monitor
Channels	3 (external shunts)
Bus voltage	0-26 V
Interface	I2C / SMBus
Alerts	Warning + critical (open-drain)
Supply	2.7-5.5 V
Package	VQFN-16

Ordering variants

Same part, different packaging or reel option.

INA3221AIRGVR (VQFN-16)
INA3221AIRGVT (VQFN-16, small reel)

CAD (KiCad official)

Symbol: Power_Management:INA3221 (KiCad official)
Footprint: Package_DFN_QFN:Texas_RGV0016A_VQFN-16-1EP_4x4mm_P0.65mm_EP2.1x2.1mm
3D model: VQFN-16 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Texas Instruments datasheet (50 pp, sha256 01dd1c52a7675638, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF