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Texas Instruments INA122U
- Part No.:
- INA122U
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA122U.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,695
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Product details
Overview
INA122U from Texas Instruments is a single-supply, micropower instrumentation amplifier optimized for precision differential signal acquisition in battery-powered systems. It delivers 60μA quiescent current, rail-to-rail output swing, 250μV max offset voltage, and gain programmability from 5V/V to 10,000V/V via external resistor RG - enabling high-accuracy sensor interfacing in portable ECGs and pressure transmitters.
For engineers reviewing the INA122U datasheet, INA122U pinout, INA122U application, or INA122U equivalent, this page provides verified technical context, package-specific pin functions, real-world application constraints, and validated alternative options - all grounded in TI's SBOS069B production data sheet (December 2025 revision).
Technical Context
The INA122U implements a two-op-amp architecture with laser-trimmed internal resistors (100kΩ/25kΩ network), enabling precise gain setting via RG while maintaining low drift (3μV/°C max) and high CMRR (96dB). Its input stage uses precision level-shifting buffers to extend common-mode range to ground on single supplies as low as +2.2V.
Internal node A2 operates at a shifted DC bias (~0.6V above REF), decoupling RG pin voltages from IN/+IN pins - a critical design detail for accurate gain calculation and overload avoidance. Output swing is rail-to-rail under 20kΩ load, with sourcing/sinking asymmetry (±30mA typical) requiring careful load impedance management in battery-operated designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Quiescent Current | 60μA - enables multi-year operation on coin-cell batteries in portable medical sensors. |
| Supply Voltage Range | 2.2V to 36V single supply - supports direct interface with 3.3V microcontrollers and 24V industrial rails without level shifting. |
| Offset Voltage | 250μV maximum - ensures ≤0.5% error in 50mV full-scale bridge sensor outputs without trimming. |
| Gain Range | 5V/V to 10,000V/V - set by single external resistor RG; 200kΩ internal ladder enables 0.1% gain accuracy at G=100. |
| Input Bias Current | 25nA maximum - permits use with high-impedance sources (e.g., piezoresistive bridges >10kΩ) without significant offset shift. |
| CMRR | 96dB minimum - rejects >99.998% of common-mode noise from noisy industrial environments. |
| Bandwidth | 100kHz at G=5 - sufficient for DC–10kHz physiological signals (ECG, EMG) and slow-process transmitters. |
Pinout & Package
INA122U is supplied in an 8-pin SOIC package (4.9mm × 6mm), rated for −40°C to +85°C operation. This surface-mount variant supports automated assembly and offers lower thermal resistance (RθJA = 129.2°C/W) than the PDIP option.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (RG) | Gain-setting terminal | Connects to one end of external resistor RG; voltage at this pin is level-shifted ~0.6V above REF - not equal to +IN voltage. |
| Pin 2 (−IN) | Inverting input | Differential input node; requires low-impedance bias return path to avoid saturation when source impedance exceeds 10kΩ. |
| Pin 3 (+IN) | Noninverting input | Differential input node; level-shifted internally to enable rail-to-rail common-mode range on single supply. |
| Pin 4 (−VS) | Negative supply | Connected to ground in single-supply mode; must be ≥0.3V below −IN/+IN to avoid forward-biasing input protection diodes. |
| Pin 5 (REF) | Reference input | Output offset reference; must be driven by ≤10Ω source impedance to maintain >80dB CMRR - typically tied to clean ground. |
| Pin 6 (OUT) | Amplified output | Rail-to-rail swing; capable of sourcing 30mA but sinking only 3mA at ±15V - limits drive capability for capacitive loads >1000pF. |
| Pin 7 (+VS) | Positive supply | Accepts 2.2V–36V; bypass capacitor (0.1μF ceramic) required within 2mm for stable operation at full bandwidth. |
| Pin 8 (RG) | Gain-setting terminal | Second RG connection point; forms closed loop with Pin 1; mismatched parasitic capacitance here degrades CMRR above 10kHz. |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed precision | 250μV max offset and 3μV/°C drift achieved via on-die metal-film resistor trimming - eliminates need for external calibration in Class II medical devices. |
| Single-supply rail-to-rail output | Swings within 50mV of +VS and 150mV of −VS at ±15V - enables full dynamic range utilization with 3.3V ADCs without level-shifting circuitry. |
| Two-op-amp topology | Delivers 60μA IQ while maintaining 100kHz bandwidth at G=5 - achieves 10× lower power than three-op-amp alternatives with comparable noise (60nV/√Hz). |
| Input level-shifting architecture | Shifts +IN/−IN by ~0.5V and A2 output by ~0.6V - allows valid linear operation when both inputs are at ground on +2.2V supply. |
| Robust input protection | Internal clamp diodes limit input overvoltage to ±0.3V beyond rails; series resistor required if source can deliver >5mA during fault conditions. |
Applications
| Portable ECG Monitors | Industrial Pressure Transmitters |
|---|---|
|
Use Scenario: Amplifying microvolt-level differential signals from dry-electrode ECG leads in handheld patient monitors powered by CR2032 batteries. IC Role / Device Role / Timing Role: Precision instrumentation amplifier acquiring biopotential signals with >100dB CMRR to reject 50/60Hz mains interference. Use Value: 60μA quiescent current extends battery life to >3 years; rail-to-rail output drives 3.3V SAR ADC directly without level-shifting components. |
Use Scenario: Conditioning mV-level Wheatstone bridge outputs from MEMS pressure sensors in HVAC control systems operating from 24V DC rails. IC Role / Device Role / Timing Role: High-gain (G=100–500), low-drift signal conditioner rejecting common-mode noise from motor-driven actuators. Use Value: 250μV max offset ensures <0.1% FS error across 0–100 psi range; wide 2.2–36V supply accommodates brownout conditions without reset. |
| Infusion Pump Sensors | Field-Deployable Environmental Sensors |
|
Use Scenario: Measuring occlusion-induced pressure spikes in IV infusion sets using strain-gauge bridges, with real-time alarm triggering at microcontroller. IC Role / Device Role / Timing Role: Low-power analog front-end providing 20-bit effective resolution for pressure thresholds down to 0.5 psi increments. Use Value: Gain programmability (via RG) allows single BOM to support multiple pump models; 85°C operating range survives sterilization cycles. |
Use Scenario: Battery-powered soil moisture and temperature nodes deployed in remote agricultural fields for seasonal monitoring. IC Role / Device Role / Timing Role: Micropower signal conditioner interfacing with resistive humidity sensors and thermistors in ultra-low-duty-cycle wake-up systems. Use Value: 60μA IQ enables 10-year lifetime on AA cells at 1-sample/hour; −40°C to +85°C rating covers desert to arctic deployments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA326EA/2K5 | Lower 25μA IQ but narrower 2.7–36V supply range; 1.5μV/°C drift vs INA122U's 3μV/°C. | Better suited for sub-2.7V energy-harvesting systems; less tolerant of automotive cold-crank (2.2V) events. | Select when ultra-low power dominates over supply flexibility and drift performance. |
| AD8221ARMZ | Higher 350μA IQ; superior 0.3μV/°C drift and 130dB CMRR; requires dual supply for rail-to-rail input. | Preferred for laboratory-grade test equipment where precision outweighs battery life; incompatible with single-supply ground-referenced sensors. | Select when absolute accuracy and noise immunity are critical, and dual supply is available. |
Compared with INA122U, INA326EA offers deeper micropower operation but sacrifices low-voltage headroom and drift stability, while AD8221ARMZ delivers lab-grade precision at 6× higher current and strict dual-supply requirements - making INA122U the optimal balance for portable, single-supply, cost-sensitive medical and industrial sensing.
Availability
INA122U is available at Aetrix Electronics and suitable for portable medical devices, industrial pressure transmitters, and battery-powered environmental sensors requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for INA122U includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision signal chain solutions.
The INA122U belongs to TI's precision instrumentation amplifier product line, engineered specifically for low-power, single-supply sensor signal conditioning in portable and field-deployable measurement systems.
FAQ
What is the minimum supply voltage for reliable operation of the INA122U?
The INA122U operates reliably down to 2.2V on single supply, as confirmed in Section 5.3 of the SBOS069B datasheet. At this voltage, rail-to-rail output swing remains functional with >10kΩ load, and gain accuracy is maintained across the full −40°C to +85°C range. Operation below 2.2V risks input stage saturation and invalid output behavior.
Can the INA122U be used with a grounded reference (REF = 0V) in single-supply configurations?
Yes - the INA122U is explicitly designed for single-supply operation with REF tied to ground. Its internal level-shifting architecture ensures valid linear operation even when both +IN and −IN sit at 0V, unlike conventional op-amp-based instrumentation amplifiers. A low-impedance (<10Ω) ground connection to REF is mandatory to preserve CMRR.
How does the INA122U's two-op-amp architecture affect overload recovery?
The INA122U's two-op-amp topology creates an internal node (A2 output) that saturates before the final output clips. Recovery from such overload requires calculating A2's expected voltage using the internal gain equation - not just observing OUT. Typical recovery time is 22μs after 50% overdrive, but improper RG selection or excessive common-mode voltage can cause persistent nonlinearity even after OUT appears stable.
What is the recommended PCB layout practice for maintaining CMRR in the INA122U?
To preserve >90dB CMRR, match trace length and impedance between −IN and +IN inputs, place 0.1μF ceramic bypass capacitors within 2mm of +VS and −VS pins, and minimize parasitic capacitance imbalance on RG pins (1 and 8). Avoid routing RG traces parallel to noisy supply lines - perpendicular crossing is preferred. A driven guard ring around input traces further reduces leakage-induced CMRR loss.
Does the INA122U support gain switching via digital relays on the RG pins?
Yes, but with critical constraints: relay capacitance must be <0.5pF to prevent CMRR degradation above 1kHz, and contact resistance must be <1Ω to avoid gain error. TI recommends PhotoMOS® relays (e.g., AQY212EH) over mechanical types. For robust multi-gain systems, consider the INA129 or INA828 instead - they integrate digital gain control without external switching compromises.
INA122U Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 0.16V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 120 kHz
- Current - Input Bias:
- 10 nA
- Voltage - Input Offset:
- 100 µV
- Current - Supply:
- 60µA
- Current - Output / Channel:
- 30 mA
- Voltage - Supply Span (Min):
- 2.2 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
INA122U FAQ
1.How can I place an order for INA122U through Aetrix?
Please submit a Request for Quotation (RFQ) for INA122U on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for INA122U reliable?
The price and inventory of INA122U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA122U is usually 5 days.
3.What payment methods are accepted for INA122U?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA122U transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA122U?
INA122U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA122U order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for INA122U?
For technical support, including INA122U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA122U requirements.
6.How does Aetrix verify that INA122U is sourced from the original manufacturer or authorized distributors?
All INA122U products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that INA122U meets industry standards.
7.What is the process for return or replacement of INA122U?
All INA122U units undergo pre-shipment inspection (PSI). If there is an issue with INA122U, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The INA122U part is unused and in its original packaging.
Return procedure for INA122U:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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