INA2181 - 26V Dual-Channel Current Sense Amp | Texas Instruments
MPN： INA2181 ✓ 啟用中INA2181 概覽
A current sense amplifier (also called a current-shunt monitor) is a specialized difference amplifier that extracts a small differential voltage developed across a shunt resistor riding on a large common-mode voltage, and translates it to a ground-referenced output. Within the power-management IC hierarchy, current sense amplifiers sit alongside fuel gauges and monitors as essential building blocks of power supervision, telemetry, and protection subsystems.
Key features include a wide input common-mode range of -0.2V to 26V independent of the supply voltage, four factory-calibrated gain options (A1 = 20 V/V, A2 = 50 V/V, A3 = 100 V/V, A4 = 200 V/V), and a 350kHz bandwidth that supports fast transient monitoring and cycle-by-cycle current protection. A shared reference (REF) pin allows bi-directional current measurement by offsetting the output for both charging and discharging directions. The device operates from a 2.7V to 5.5V supply over an extended temperature range of -40C to +125C.
Architecturally, the INA2181 belongs to the INA181 (INAx181) family, which also includes the single-channel INA181 (SOT-23/SC70) and quad-channel INA4181 (TSSOP-20). This dual-channel integration halves solution size and cost in applications that monitor two rails or both ends of a battery.
Typical applications include battery charging and discharging monitoring, power supply and DC-DC converter current telemetry, motor control current feedback, load management, and industrial automation. The 350kHz bandwidth and fast 1us settling make it suitable for peak-current limit implementations in power converters.
When designing, select the shunt resistor so the full-scale shunt voltage stays within the 10mV-to-100mV optimal range for your gain option, and use a Kelvin (4-wire) connection to the shunt to preserve accuracy. The REF pin must be driven from a low-impedance source to avoid gain error.
直接替換替代品，適用於 INA2181 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： INA2181 （相同外形與佔位） — 差異在於 Output Type, Package, RoHS Status, Channels, Operating Temperature Range.
INA2181A2IDGSR
✅ 直接替換聯絡詢價
查看資料表 →INA2181A3IDGST
✅ 直接替換📋 參考替代品（不在目錄中）
INA2181A4IDSQR
✅ 直接替換聯絡詢價
查看資料表 →INA2181-Q1
✅ 直接替換📋 參考替代品（不在目錄中）
INA2181 最大額定值與電氣特性
| Product Type | Dual-channel current sense amplifier |
| Number of Channels | 2 |
| Input Common-Mode Voltage Range | -0.2 V to 26 V |
| Bandwidth | 350 kHz |
| Gain Options | 20 V/V (A1), 50 V/V (A2), 100 V/V (A3), 200 V/V (A4) |
| 輸出類型 | Voltage output (rail-to-rail) |
| 工作溫度範圍 | -40C to +125C |
| Sensing Mode | Low-side and high-side, bi-directional |
| 封裝 | 10-VSSOP (DGS) and 10-WSON |
| 安裝類型 | Surface Mount |
| Reference Pin | Yes (REF, shared bi-directional offset) |
| RoHS 狀態 | Compliant |
| Automotive Grade Option | INA2181-Q1 (AEC-Q100) |
INA2181 腳位配置
| 腳位 1 | OUT1 — Channel 1 voltage output |
| 腳位 2 | GND — Ground reference |
| 腳位 3 | REF — Reference input for bi-directional output offset (shared) |
| 腳位 4 | INP2 — Channel 2 non-inverting shunt input |
| 腳位 5 | INN2 — Channel 2 inverting shunt input |
| 腳位 6 | OUT2 — Channel 2 voltage output |
| 腳位 7 | NC — No connection (verify per datasheet package pinout) |
| 腳位 8 | V+ — Supply voltage (2.7V to 5.5V class) |
| 腳位 9 | INN1 — Channel 1 inverting shunt input |
| 腳位 10 | INP1 — Channel 1 non-inverting shunt input |
典型應用
INA2181 適用於 6 應用s: Battery Charge/Discharge Monitoring, DC-DC Converter Current Telemetry, Motor Control Current Feedback, Automotive Body and Power Modules, Industrial Automation Power Supervision, USB-C and Consumer Port Load Monitoring.
Battery Charge/Discharge Monitoring
The INA2181 fits battery systems because its bi-directional REF-pin architecture measures both charging and discharging current through a single shunt, and its dual channels can monitor pack current and a second rail simultaneously. With a -0.2V to 26V common-mode range, it works directly on 12V and 24V battery buses. The 350kHz bandwidth captures inrush and transient charge events that slower monitors miss, while rail-to-rail output keeps the full ADC range usable near zero current.
推薦
DC-DC Converter Current Telemetry
In switching power supplies, the INA2181 provides cycle-by-cycle current visibility thanks to its 350kHz bandwidth and fast settling, enabling peak current limiting and health monitoring of each converter rail. The dual channels let one IC supervise both the input and output sides of a buck or boost stage. With common-mode up to 26V, it connects across input-current shunts on 12V and 24V intermediate bus rails while powered from the controller's 5V or 3.3V supply.
推薦
Motor Control Current Feedback
The INA2181 serves motor drives by sensing phase or bus current quickly enough for torque-loop feedback and overcurrent protection. Its two channels can monitor two motor phases with a single device, halving the sensing BOM versus single-channel parts. The 350kHz bandwidth preserves current waveform detail for FOC algorithms running on MCUs such as TMS320F28004x, and the wide common-mode range tolerates PWM-induced common-mode swings on high-side shunts up to 26V.
推薦
Automotive Body and Power Modules
For automotive loads such as LED lighting, pumps, and ECUs, the INA2181-Q1 variant is AEC-Q100 qualified and operates from -40C to +125C per TI documentation. Its 26V common-mode range covers 12V load-dump-adjacent rails with margin, and the dual channels allow monitoring of both high-side supply current and a return path. Cost-optimized pricing suits high-volume body electronics where every cent of BOM matters.
推薦
Industrial Automation Power Supervision
In PLC I/O modules and factory automation racks, the INA2181 monitors 24V field-supply current across dual channels, providing fault and load diagnostics to the system controller. The voltage output interfaces directly to ADCs without extra level shifting, and the low cost enables per-channel sensing across many modules. Its extended -40C to +125C operation and small 10-VSSOP footprint suit dense industrial boards with limited space and wide ambient ranges.
推薦
USB-C and Consumer Port Load Monitoring
Consumer adapters and USB-C power delivery sources use the INA2181 to monitor port current for overload detection and power negotiation feedback. The 2.7V-to-5.5V supply operation matches logic rails, while the 26V common-mode range safely observes the input side of charger front ends. The compact 10-VSSOP package fits space-constrained dongle and adapter designs, and low unit cost around $0.31 at volume as of 2026-08-30 keeps consumer BOMs competitive.
推薦
推薦產品摘要
工程參考資料，適用於 INA2181 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | INA2181A2IDGSR | INA2181-Q1 | INA181A2IDGKR |
|---|---|---|---|---|
| Package | 10-VSSOP (DGS) / 10-WSON | 10-VSSOP (DGS) - same | 10-VSSOP (DGS) - same | SC70-6 - different footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Number of Channels | 2 | 2 | 2 | 1 |
| Gain | 20 V/V (A1) | 50 V/V | 20/50/100/200 V/V by suffix | 50 V/V |
| Input Common-Mode Range | -0.2 V to 26 V | -0.2 V to 26 V | -0.2 V to 26 V | -0.2 V to 26 V |
| Bandwidth | 350 kHz | 350 kHz | 350 kHz | 350 kHz |
| Automotive Grade | No (standard grade) | No | Yes (AEC-Q100) | No |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C |
主要差異化特點
- Dual-channel integration halves BOM cost (對比INA181A2IDGKR)
- Automotive-qualified variant available (對比INA2181A2IDGSR)
- Wide common-mode range independent of supply (對比generic 5.5V-max current sense amps)
設計說明
Route Kelvin (4-wire) sense traces directly from the shunt resistor pads to the INP and INN pins. Do not share current-carrying traces with sense lines, since milliohms of trace resistance creates gain error at 20 V/V gain. Keep the two sense traces a symmetric, closely-coupled pair to reject noise, and place the INA2181 within a few millimeters of the shunt. Add a small RC filter (e.g., 10 ohm/100 nF) at the inputs if large dV/dt transients are present, accepting a small bandwidth reduction.
Drive the shared REF pin from a low-impedance source such as a buffered divider or reference IC; the REF pin impedance interacts with the internal resistor network and a high-impedance drive shifts both output offset and gain accuracy. Decouple V+ with a 100 nF ceramic capacitor placed within 2 mm of the pin. The REF offset determines zero-current output, so choose it so both charge and discharge current directions keep the rail-to-rail output within its linear range.
Select the gain suffix before finalizing the shunt value: A1 (20 V/V) suits large shunts up to ~100 mV full-scale, while A4 (200 V/V) suits low-current, small-shunt designs where shunt power dissipation dominates. Mixing gain suffixes during BOM substitution silently changes scaling by 2.5x-10x and can saturate the output at full load. Verify the pinout against the TI datasheet for your exact package (VSSOP vs WSON) before layout release.
合規資訊
Standard INA2181 is RoHS compliant per TI product page; INA2181-Q1 variant is AEC-Q100 qualified for automotive use. REACH and halogen-free status not stated in verified data.
