INA2181 26V Dual-Channel Current Sense Amp | TI | Gain 20 V/V
MPN: INA2181A1IDGSR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.09 | $1.09 |
| 10 | $0.98 | $9.80 |
| 100 | $0.79 | $79.00 |
| 500 | $0.64 | $320.00 |
| 1,000 | $0.52 | $520.00 |
INA2181A1IDGSR Overview
A current sense amplifier (also called a current-shunt monitor) is a specialized difference amplifier that extracts a small differential shunt voltage riding on a large common-mode voltage and converts it to a ground-referenced single-ended signal. Within the signal chain hierarchy it sits between the shunt resistor and an ADC or comparator, serving as a front-end element of power management and battery monitoring systems.
Key features include a wide 2.7V to 26V common-mode range that is independent of the 2.7V to 5.5V supply, 350kHz bandwidth for fast load-transient monitoring, bidirectional operation with a reference pin for charging/discharging current measurement, and factory-calibrated gain options (A1 = 20 V/V, A2 = 50 V/V, A3 = 100 V/V, A4 = 500 V/V) that eliminate gain-setting resistors. The zero-drift architecture delivers low offset for small shunt voltages.
The dual channels share one package, halving board area versus two single-channel monitors such as the INA181. Rail-to-rail output swings close to the supply rails, maximizing ADC dynamic range. All device options are specified from -40C to +125C.
Typical applications include battery current monitoring in portable and industrial equipment, DC motor drive phase and bus current sensing, telecom and server power supply current telemetry, and load-current supervision in 12V/24V rails feeding TI C2000 or MSPM0 MCUs.
Design tip: keep the shunt voltage in the 10 mV to 100 mV range at full load - large enough to swamp offset error, small enough to limit shunt power dissipation. Route Kelvin sense traces directly to the shunt pads to preserve accuracy.
Drop-in alternatives for INA2181A1IDGSR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with INA2181A1IDGSR (same form factor and footprint) — differing in Output Type, Package, Common-Mode Voltage Range, RoHS Status, Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
INA2181-Q1
✅ Drop-In📋 Reference alternative (not in catalog)
INA2181A2IDGSR
✅ Drop-In✓ In Stock
$0.19 / Unit
View Datasheet →INA2181A3IDGST
✅ Drop-In📋 Reference alternative (not in catalog)
INA2181A4IDSQR
✅ Drop-In✓ In Stock
$0.18 / Unit
View Datasheet →INA2181A1IDGSR Maximum Ratings & Electrical Characteristics
| Channels | 2 |
| Common-Mode Voltage Range | -4 V to 26 V (survives, sensing to 26 V) |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Bandwidth | 350 kHz |
| Gain (INA2181A1) | 20 V/V |
| Gain Options | 20, 50, 100, 500 V/V (A1/A2/A3/A4) |
| Output Type | Voltage output, rail-to-rail, bidirectional |
| Sensing Location | Low-side or high-side |
| Operating Temperature | -40C to +125C |
| Package | 10-VSSOP (DGS) |
| Mounting Type | Surface Mount |
| Family | INAx181 (INA181 / INA2181 / INA4181) |
| RoHS Status | Compliant |
| Automotive Grade Option | INA2181-Q1 (AEC-Q100) |
INA2181A1IDGSR Pin Configuration
| Pin 1 | REF1 — Channel 1 reference input for bidirectional output offset |
| Pin 2 | IN1- — Channel 1 inverting shunt input |
| Pin 3 | IN1+ — Channel 1 non-inverting shunt input |
| Pin 4 | GND — Ground |
| Pin 5 | IN2+ — Channel 2 non-inverting shunt input |
| Pin 6 | IN2- — Channel 2 inverting shunt input |
| Pin 7 | REF2 — Channel 2 reference input |
| Pin 8 | OUT2 — Channel 2 voltage output |
| Pin 9 | VS — Power supply, 2.7V to 5.5V |
| Pin 10 | OUT1 — Channel 1 voltage output |
Typical Applications
INA2181A1IDGSR is suitable for 6 applications: Battery Current Monitoring, DC Motor Drive Current Sensing, Telecom and Server Power Rails, Industrial 24V PLC I/O Current Supervision, Automotive Body Electronics Current Monitoring, Portable and IoT Device Power Profiling.
Battery Current Monitoring
The INA2181 fits battery current monitoring because its bidirectional architecture with REF pin offset measures both charge and discharge current on a single shunt, and its 26V common-mode range covers 12V and 24V battery buses independently of the 2.7V to 5.5V logic supply. Two channels allow simultaneous monitoring of battery current and load current from one package, halving solution size versus two INA181s. Place the amplifier close to the shunt with Kelvin-sensed traces; the 350kHz bandwidth captures fast charge-transient events that slower monitors average out, improving coulomb-counting accuracy and protection response in portable and industrial battery packs.
Recommended
DC Motor Drive Current Sensing
In DC and BLDC motor drives, the INA2181's two channels monitor bus current and phase current simultaneously with 350kHz bandwidth, fast enough to track PWM-related current ripple and support cycle-by-cycle overcurrent protection. The 26V common-mode tolerance survives motor back-EMF and inductive kick on 12V/24V rails. Its voltage output connects directly to the ADC inputs of TI C2000 real-time MCUs such as TMS320F280041C-Q1 without extra conditioning. Choose the A3 or A4 gain variant for small shunt resistors to limit conduction loss while preserving resolution for torque control loops.
Recommended
Telecom and Server Power Rails
The INA2181 provides cost-effective current telemetry on -48V-derived intermediate buses and 12V server power rails. Its wide common-mode range and rail-to-rail output maximize ADC dynamic range when powered from 5V, while the zero-drift core keeps offset low for the small shunt voltages typical of high-current, low-drop rails. The dual channels let one package monitor both input and output current of a DC-DC brick such as the TPS53315, enabling efficiency and fault reporting to a hot-swap controller or BMC. The 350kHz bandwidth also catches fast fault transients ahead of software-level supervision.
Recommended
Industrial 24V PLC I/O Current Supervision
Industrial programmable-logic controllers routinely supervise 24V field-side loads. The INA2181 tolerates the 24V common-mode directly from a 3.3V or 5V logic supply, and its -40C to +125C rating suits cabinet and edge installations. One dual-channel package supervises two digital output channels, reporting load current to an ADC and driving comparator thresholds for open-wire or short-circuit detection. Channel-to-channel matching within one die improves measurement consistency across the two monitored loads, simplifying firmware calibration compared with two discrete single-channel monitors like the INA181.
Recommended
Automotive Body Electronics Current Monitoring
For AEC-Q100 applications, the INA2181-Q1 variant monitors loads such as LED lamps, pumps, and actuators on 12V automotive rails. The 26V common-mode rating covers load-dump-adjacent conditions at the amplifier input, and bidirectional measurement supports loads that regenerate energy, such as motor-driven flaps. Its voltage output feeds TI automotive MCUs like MSPM0G3207-Q1 for diagnostic current signatures (open load, short, stuck-on). The cost-optimized INAx181 architecture makes per-load monitoring affordable even in high-channel-count body control modules, replacing discrete op-amp shunt circuits with a calibrated monolithic solution.
Recommended
Portable and IoT Device Power Profiling
Battery-powered IoT devices benefit from the INA2181's low supply requirement (2.7V) and small 10-VSSOP footprint for in-circuit current profiling. The A4 (500 V/V) gain variant resolves microamp sleep-state currents using a small shunt, while the second channel monitors burst transmit currents on the same rail - the 350kHz bandwidth captures radio TX bursts that multimeters miss. Pairing with the low-power MSPM0L1305-Q1 MCU or ADS7042 ADC enables always-on energy telemetry. The REF pin allows output offset so the full bidirectional range maps into a unipolar ADC input range.
Recommended
Recommended Products Summary
Engineering reference data for INA2181A1IDGSR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | INA2181-Q1 | INA2181A2IDGSR | INA2181A4IDSQR | INA4181A1 |
|---|---|---|---|---|---|
| Package | 10-VSSOP (DGS) | 10-VSSOP - same | 10-VSSOP (DGS) - same | 10-VSSOP (DGS) - same | 20-TSSOP - different |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Channels | 2 | 2 | 2 | 2 | 4 |
| Gain | 20 V/V (A1) | 20/50/100/500 V/V by suffix | 50 V/V | 500 V/V | 20 V/V |
| Bandwidth | 350 kHz | 350 kHz | 350 kHz | 350 kHz | 350 kHz |
| Common-Mode Range | to 26 V | to 26 V | to 26 V | to 26 V | to 26 V |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| Automotive Grade | No (standard) | Yes (AEC-Q100) | No | No | INA4181-Q1 available |
Key Differentiators
- Dual-channel integration halves board area (vs INA181)
- Automotive AEC-Q100 option (vs INA2181A2IDGSR (standard grade))
- Gain-scalability within same footprint (vs INA2181A4IDSQR)
Design Notes
Use Kelvin (4-wire) sensing to the shunt resistor: route the IN+ and IN- traces directly to the shunt pads, not to shared power traces, to avoid adding trace resistance to the measurement. Keep the differential pair short and symmetric. With 20 V/V gain (A1), just 1 mV of unwanted series resistance drop becomes 20 mV of output error - significant against a 3.3V rail budget. Place 100 nF decoupling at VS and 10 nF on REF pins if driven by a divider.
The REF pin must be driven from a low-impedance source (buffer or dedicated REF output); a resistive divider alone shifts gain accuracy because REF current flows through the divider. Also select the shunt for 10 mV to 100 mV full-scale drop: below 10 mV, offset error dominates; above 100 mV, shunt power dissipation (I^2R) and reduced load voltage become problems. Balance these against the fixed gains - pick gain variant first, then shunt value.
The 350kHz bandwidth means the INA2181 will faithfully pass shunt noise up to that frequency into the output. If driving a low-bandwidth ADC, add a first-order RC filter (e.g., 1 kOhm, 10 nF gives ~16 kHz cutoff) between the output and ADC pin to limit noise folding. For fast overcurrent comparators, use the unfiltered output for minimum response delay.
Compliance Information
Standard INA2181 is RoHS-compliant per TI product page. The INA2181-Q1 variant is AEC-Q100 qualified for automotive applications.
