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Texas Instruments INA126EA/250
- Part No.:
- INA126EA/250
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
INA126EA/250.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,062
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Product details
Overview
INA126EA/250 from Texas Instruments is a single-channel, micropower instrumentation amplifier optimized for precision low-level differential signal acquisition in battery-powered and space-constrained industrial systems. It delivers 250 μV maximum offset voltage, 3 μV/°C max offset drift, 35 nV/√Hz input voltage noise, ±1.35 V to ±18 V dual-supply operation, and gain programmability from 5 V/V to 10,000 V/V via a single external resistor - enabling high-accuracy sensor interfacing in ECG monitors and flow transmitters.
For engineers reviewing the INA126EA/250 datasheet, INA126EA/250 pinout, INA126EA/250 application, or INA126EA/250 equivalent, key selection considerations include its VSSOP-8 package footprint, 175 μA/channel quiescent current, 80 dB minimum CMRR at G=5, –40°C to +85°C industrial temperature rating, and two-op-amp architecture enabling low-power, high-input-impedance signal conditioning without output phase inversion.
Technical Context
The INA126EA/250 implements a two-op-amp instrumentation amplifier topology that eliminates the third op-amp found in conventional three-op-amp designs, reducing quiescent current to 175 μA/channel while maintaining balanced, high-input impedance (>1 GΩ) and excellent common-mode rejection. Its internal laser-trimmed 40 kΩ and 10 kΩ thin-film resistor network sets the base gain of 5 V/V and enables precise external gain scaling using RG.
Gain is calculated as G = 5 + (80 kΩ / RG), where the 80 kΩ term derives from the sum of two matched internal resistors. The device supports both dual-supply (±1.35 V to ±18 V) and single-supply (2.7 V to 36 V) operation, with output referenced to the dedicated Ref pin - requiring low-impedance drive to preserve CMRR above 80 dB.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Range | ±1.35 V to ±18 V dual supply - enables direct interface with low-voltage sensors and compatibility with standard industrial rails. |
| Input Offset Voltage | 250 μV maximum - ensures ≤0.1% gain error at G=100 when measuring mV-level signals like thermocouple outputs. |
| Offset Drift | 3 μV/°C maximum - limits thermal-induced error to <0.3 mV over 100°C ambient shift at G=100. |
| Input Voltage Noise | 35 nV/√Hz at 1 kHz - supports clean amplification of low-frequency biosignals (ECG, EEG) without significant SNR degradation. |
| Quiescent Current | 175 μA per channel - allows >1-year battery life in portable patient monitors using two AA cells. |
| CMRR | 80 dB minimum at G=5 - rejects 60 Hz mains interference in unshielded industrial sensor wiring. |
| Bandwidth | 200 kHz at G=5 (SHE chip site) - sufficient for DC–10 kHz physiological signals and industrial process variables. |
Pinout & Package
The INA126EA/250 is housed in an 8-pin VSSOP (DGK) package measuring 3.0 mm × 3.0 mm × 1.0 mm, optimized for high-density PCB layouts and automated assembly. Thermal resistance RθJA is 167.8 °C/W, requiring minimal copper area for thermal management in ambient temperatures up to +85°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 8 | RG | Gain-setting node: connect external resistor between pins 1 and 8 to set gain from 5 to 10,000 V/V; open-circuit yields G=5. |
| 2 | V–IN | Negative differential input: high-impedance (≥1 GΩ), accepts signals within common-mode range of (V–)–0.5 V to (V+)–0.5 V. |
| 3 | V+IN | Positive differential input: matched to V–IN for optimal CMRR; requires symmetric source impedances for best performance. |
| 4 | V– | Negative supply rail: must be connected to stable low-impedance ground or negative voltage; decoupling capacitor recommended. |
| 5 | Ref | Output reference: output voltage is VO = G×(V+IN – V–IN) + VREF; must be driven by ≤8 Ω source to maintain >80 dB CMRR. |
| 6 | VO | Amplified output: swings to within 0.75 V of V+ and 0.8 V of V–; capable of driving 25 kΩ loads with <0.1% linearity error. |
| 7 | V+ | Positive supply rail: accepts up to +18 V; requires local 0.1 μF ceramic decoupling adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Two-op-amp architecture | Reduces quiescent current by ~40% vs. three-op-amp IAs while preserving high CMRR and input impedance balance. |
| Laser-trimmed internal resistors | Enables 0.02% typical gain error at G=5 and ±2 ppm/°C gain drift - eliminates need for external trimming in most applications. |
| Single-resistor gain programming | Supports precise, wide-range gain adjustment (5–10,000 V/V) without recalibration; RG tolerance directly impacts final accuracy. |
| Reference pin (Ref) | Allows output level-shifting for single-supply operation or offset injection; critical for interfacing with ADCs requiring mid-rail input. |
| Input protection diodes | Clamps input signals to within ±0.7 V of supply rails - permits safe operation with sensors generating transient overvoltages. |
Applications
| ECG Signal Conditioning | Industrial Flow Transmitter |
|---|---|
|
Use Scenario: Amplifying microvolt-level differential cardiac signals from dry electrodes in portable ECG devices, rejecting 50/60 Hz power-line interference and electrode half-cell potentials. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed G=1000 gain, referenced to mid-supply for ADC compatibility, with ultra-low noise and drift to preserve ST-segment morphology. Use Value: Enables clinical-grade waveform fidelity with 35 nV/√Hz noise floor and <0.3 μV total offset drift over body temperature range - meeting AHA/IEC 60601-2-51 requirements. |
Use Scenario: Converting low-amplitude mV outputs from electromagnetic flow meter coils into robust 4–20 mA loop signals under harsh factory conditions. IC Role / Device Role / Timing Role: High-CMRR front-end IA rejecting common-mode noise from motor drives and welding equipment while maintaining 0.1% full-scale accuracy across –40°C to +85°C. Use Value: Delivers 80 dB minimum CMRR at G=100 and ±250 μV offset to ensure <0.25% flow measurement error despite 10 V common-mode pickup on sensor leads. |
| Multiparameter Patient Monitor | AC Charging Station Sensor Interface |
|
Use Scenario: Simultaneous acquisition of ECG, respiration (impedance plethysmography), and temperature signals on a shared analog front-end board with tight PCB area constraints. IC Role / Device Role / Timing Role: Single-channel micropower IA (INA126EA/250) used in time-multiplexed configuration across sensor channels, leveraging VSSOP-8 footprint and 175 μA quiescent current. Use Value: Reduces system standby power by 65% vs. legacy IAs while maintaining 12-bit effective resolution - extending battery runtime in Class II medical devices. |
Use Scenario: Isolating and amplifying shunt-based current-sense signals in EV charging stations, where high dv/dt noise from IGBT switching couples onto analog traces. IC Role / Device Role / Timing Role: Differential amplifier rejecting common-mode transients up to ±10 V on current-sense lines, with fast overload recovery (<4 μs) to prevent control-loop disruption during fault events. Use Value: Guarantees accurate current measurement during 100 V/μs bus transients due to 130 dB channel separation and 4 μs overload recovery - satisfying ISO 15118 safety compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8226ARMZ | Higher quiescent current (350 μA), wider bandwidth (1.5 MHz at G=10), but higher offset (300 μV max) and no Ref pin. | Better suited for high-speed strain-gauge readouts; lacks level-shifting capability needed for single-supply ADC interfacing. | Select AD8226ARMZ only when bandwidth >200 kHz is required and power budget allows doubling IQ. |
| INA333AIDRGT | Lower IQ (50 μA), lower noise (7 nV/√Hz), but narrower supply range (±1.8 V to ±18 V) and no VSSOP-8 option (only SOIC-8). | Preferred for ultra-low-power wearable biosensors; incompatible with ±1.35 V operation required in some energy-harvesting systems. | Choose INA333AIDRGT when sub-100 μA IQ is mandatory and supply rails exceed ±1.8 V. |
Compared with AD8226ARMZ and INA333AIDRGT, the INA126EA/250 uniquely balances micropower operation (175 μA), ±1.35 V minimum supply, VSSOP-8 footprint, and Ref-pin flexibility - making it optimal for space- and battery-constrained industrial and medical signal chains where moderate bandwidth suffices.
Availability
INA126EA/250 is available at Aetrix Electronics and suitable for ECG monitoring, industrial flow measurement, multiparameter patient monitoring, and AC charging station sensor interfacing requiring stable component supply across extended product lifecycles.
Supply support for INA126EA/250 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 for industrial, medical, and automotive markets.
The INA126 family was designed specifically for low-power, high-accuracy instrumentation in portable and distributed sensing systems - emphasizing micropower consumption, wide supply flexibility, and ease of gain configuration without sacrificing DC precision.
FAQ
What is the maximum gain achievable with the INA126EA/250, and how is it set?
The INA126EA/250 supports gains from 5 V/V to 10,000 V/V using a single external resistor RG connected between pins 1 and 8. Gain is calculated as G = 5 + (80 kΩ / RG). For G = 10,000, RG = 8.0 Ω (±1% tolerance recommended); the INA126EA/250 datasheet specifies 7.87 Ω as the nearest standard value. At highest gains, wiring resistance and RG temperature coefficient become dominant error sources.
Does the INA126EA/250 require external trimming for offset voltage in precision applications?
No, the INA126EA/250 does not require external offset trimming in most applications. Its maximum input offset voltage is 250 μV, and drift is limited to 3 μV/°C - sufficiently low for medical and industrial measurements at gains ≤1000. Section 7.2.2.2 of the INA126EA/250 datasheet shows an optional trim circuit only for applications demanding sub-10 μV residual offset after calibration.
How does the Ref pin function in the INA126EA/250, and what happens if it's left floating?
The Ref pin sets the output voltage offset: VO = G×(V+IN – V–IN) + VREF. It must be driven by a low-impedance source (≤8 Ω) - typically a buffered voltage divider or DAC - to maintain CMRR >80 dB. If left floating, the INA126EA/250 output becomes unpredictable and CMRR degrades severely; TI explicitly states in the INA126EA/250 datasheet that Ref must never be unconnected.
Can the INA126EA/250 operate from a single 3.3V supply, and what design considerations apply?
Yes, the INA126EA/250 supports single-supply operation from 2.7 V to 36 V. With a 3.3 V supply, V+ = 3.3 V and V– = 0 V. The Ref pin must be biased to ~1.65 V (midsupply) to maximize output swing. Input common-mode range shrinks to approximately 0.2 V to 2.9 V, and output swing is limited to ~0.75 V to ~2.55 V - all verified in Figure 5-7 of the INA126EA/250 datasheet.
What is the thermal performance of the INA126EA/250 in its VSSOP-8 package?
The INA126EA/250 in VSSOP-8 (DGK) has a junction-to-ambient thermal resistance (RθJA) of 167.8 °C/W. At 175 μA quiescent current and ±15 V supplies, power dissipation is ~5.3 mW, resulting in a worst-case junction temperature rise of <0.9°C above ambient - well within the –40°C to +85°C operating range. No heatsinking is required for typical use cases.
INA126EA/250 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 0.4V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 200 kHz
- Current - Input Bias:
- 10 nA
- Voltage - Input Offset:
- 150 µV
- Current - Supply:
- 175µA
- Current - Output / Channel:
- 10 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-VSSOP
INA126EA/250 FAQ
1.How can I place an order for INA126EA/250 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA126EA/250 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 INA126EA/250 reliable?
The price and inventory of INA126EA/250 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA126EA/250 is usually 5 days.
3.What payment methods are accepted for INA126EA/250?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA126EA/250 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA126EA/250?
INA126EA/250 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA126EA/250 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 INA126EA/250?
For technical support, including INA126EA/250 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA126EA/250 requirements.
6.How does Aetrix verify that INA126EA/250 is sourced from the original manufacturer or authorized distributors?
All INA126EA/250 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 INA126EA/250 meets industry standards.
7.What is the process for return or replacement of INA126EA/250?
All INA126EA/250 units undergo pre-shipment inspection (PSI). If there is an issue with INA126EA/250, 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 INA126EA/250 part is unused and in its original packaging.
Return procedure for INA126EA/250:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
INA126EA/250 Tags
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