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Texas Instruments INA126PA
- Part No.:
- INA126PA
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
INA126PA.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,077
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Product details
Overview
INA126PA from Texas Instruments is a single-channel, micropower instrumentation amplifier optimized for precision low-level signal conditioning in battery-powered and space-constrained industrial systems. It delivers 175 μA/channel quiescent current, ±1.35V to ±18V dual-supply operation, 250 μV max input offset voltage, 3 μV/°C max offset drift, and 35 nV/√Hz input voltage noise - enabling high-fidelity sensor interfacing in ECG monitors and flow transmitters.
For engineers reviewing the INA126PA datasheet, INA126PA pinout, INA126PA application, or INA126PA equivalent, key selection considerations include its two-op-amp architecture for low power, gain-setting via single external resistor (5–10,000 V/V), rail-to-rail output swing capability, 8-pin PDIP package compatibility, and guaranteed performance across –40°C to +85°C industrial temperature range.
Technical Context
The INA126PA implements a two-op-amp instrumentation amplifier topology that eliminates the third op-amp found in conventional three-op-amp designs, reducing quiescent current by ~40% while preserving high common-mode rejection and balanced input impedance. Its internal laser-trimmed 40kΩ/10kΩ resistor network enables precise gain scaling with only one external resistor (RG) connected between pins 1 and 8.
This architecture supports both dual-supply (±1.35V to ±18V) and single-supply (2.7V to 36V) operation, with the REF pin (pin 5) serving as output reference level - requiring low-impedance drive to maintain ≥74 dB CMRR at G=5 and full specified accuracy. Input bias current remains ≤25 nA (max) across temperature, enabling direct connection to high-impedance sensors like thermocouples and strain gauges without significant error.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | ±1.35V to ±18V dual supply - enables operation from coin-cell batteries up to industrial rails without level-shifting circuitry. |
| Quiescent Current | 175 μA per channel - allows continuous operation for >1 year on a single CR2032 battery in portable sensor nodes. |
| Input Offset Voltage | 250 μV maximum - ensures <0.01% gain error at G=250 for 10mV differential signals in precision measurement. |
| Offset Drift | 3 μV/°C maximum - limits thermal-induced error to <0.3 mV over 100°C ambient shift at G=100. |
| Gain Range | 5 V/V to 10,000 V/V via single RG resistor - simplifies design of scalable front-ends for multi-range industrial transmitters. |
| Input Voltage Noise | 35 nV/√Hz at 1 kHz - preserves SNR for microvolt-level biopotential signals such as ECG and EEG. |
| CMRR | 74 dB minimum at G=5 - rejects 99.97% of 60 Hz mains interference when measuring small-signal bridge outputs. |
Pinout & Package
INA126PA is housed in an 8-pin plastic dual in-line package (PDIP), with 0.3-inch body width and standard through-hole mounting. The package supports manual soldering and socket-based prototyping, and provides adequate thermal dissipation (RθJA = 52.2°C/W) for ambient temperatures up to +85°C without forced airflow.
| 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 per G = 5 + 80 kΩ/RG. |
| 2 | V–IN | Negative input: high-impedance (≥1 GΩ), accepts differential signal referenced to V+IN; requires bias current return path. |
| 3 | V+IN | Positive input: matched high-impedance input; forms differential pair with V–IN for common-mode rejection. |
| 4 | V– | Negative supply rail: must be decoupled with 0.1 μF capacitor near pin to suppress supply noise coupling. |
| 5 | Ref | Output reference: sets DC level of VO; must be driven by low-impedance source (≤8 Ω) to preserve CMRR. |
| 6 | VO | Amplified output: rail-to-rail capable (within 0.75–0.95 V of rails); drives 25 kΩ load with <0.1% linearity error. |
| 7 | V+ | Positive supply rail: accepts up to +18 V; requires local 0.1 μF ceramic decoupling for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Two-op-amp architecture | Reduces quiescent current by 40% vs. traditional three-op-amp IAs while maintaining >74 dB CMRR at G=5. |
| Laser-trimmed internal resistors | Enables ±0.18% max gain error at G=5 and ±1% at G=100 without external trimming components. |
| Single-resistor gain programming | Eliminates need for matched resistor networks - simplifies BOM and layout for configurable gain stages. |
| Wide common-mode input range | Supports inputs from (V–) – 0.5 V to (V+) + 0.5 V at RS = 0 Ω, enabling direct interface to ungrounded sensors. |
| Industrial temperature rating | Guaranteed operation from –40°C to +85°C - suitable for deployment in outdoor metering and factory-floor equipment. |
Applications
| Level Transmitter | Flow Transmitter |
|---|---|
Use Scenario: Conditioning mV-level differential output from 4–20 mA loop-powered pressure sensors in water treatment plants. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing gain, common-mode rejection, and output referencing for analog signal chain front-end. Use Value: 250 μV max offset and 3 μV/°C drift ensure <±0.1% FS error over temperature, meeting ANSI/ISA-50.00.01 Class A accuracy requirements. |
Use Scenario: Amplifying low-amplitude signals from electromagnetic flow meters operating in noisy industrial environments. IC Role / Device Role / Timing Role: High-CMRR IA rejecting 60 Hz ground loops and harmonics while preserving microvolt-level flow-induced voltage differentials. Use Value: 74 dB min CMRR at G=5 suppresses >99.97% of 60 Hz interference, eliminating need for additional notch filtering in analog domain. |
| Multiparameter Patient Monitor | Electrocardiogram (ECG) |
Use Scenario: Signal conditioning stage for simultaneous acquisition of respiration, temperature, and SpO₂ analog channels in portable clinical devices. IC Role / Device Role / Timing Role: Low-power IA enabling multi-channel analog front-end with shared supply and reference architecture. Use Value: 175 μA/channel quiescent current allows 8-channel monitoring for >8 hours on a 2000 mAh Li-ion battery. |
Use Scenario: Front-end amplification of 0.5–2 mV differential cardiac signals with 60 Hz common-mode interference in bedside ECG units. IC Role / Device Role / Timing Role: Micropower instrumentation amplifier delivering high gain, low noise, and stable DC baseline for analog signal chain. Use Value: 35 nV/√Hz input noise preserves diagnostic fidelity of QRS complex morphology; 250 μV offset avoids baseline wander correction overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD620ARZ | Higher quiescent current (1.3 mA vs. 0.175 mA); better CMRR (130 dB vs. 74 dB at G=5); requires external RG but no REF pin. | Preferred in mains-powered lab equipment where power is not constrained and ultra-high CMRR is critical. | Select AD620ARZ when >100 dB CMRR is required and board space allows SOIC-8 footprint; avoid for battery-operated designs due to 7.4× higher IQ. |
| INA333AIDR | Lower IQ (50 μA), zero-drift architecture (0.1 μV/°C offset drift), but narrower supply range (±1.8V to ±5.5V) and lower bandwidth (500 kHz vs. 200 kHz at G=5). | Better suited for ultra-low-drift, low-voltage wearable biosensors; not viable for ±15V industrial transmitters. | Choose INA333AIDR for sub-μV/°C drift-critical medical wearables; use INA126PA where wide supply range and proven industrial reliability are mandatory. |
Compared with AD620ARZ and INA333AIDR, the INA126PA uniquely balances micropower operation (175 μA), wide supply flexibility (±1.35V to ±18V), and industrial-grade temperature specification - making it the optimal choice for portable, multi-range, and harsh-environment instrumentation where battery life and robustness are co-primary constraints.
Availability
INA126PA is available at Aetrix Electronics and suitable for level transmitter calibration, flow meter signal conditioning, and multiparameter patient monitor production requiring stable component supply and long-term industrial availability.
Supply support for INA126PA 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 INA126PA belongs to TI's INAx126 micropower instrumentation amplifier family, designed specifically for high-accuracy, low-power sensor signal acquisition in portable and distributed industrial measurement systems.
FAQ
What is the maximum gain achievable with the INA126PA, and how is it set?
The INA126PA supports gains from 5 V/V to 10,000 V/V using a single external resistor (RG) connected between pins 1 and 8, per the equation G = 5 + 80 kΩ/RG. For G = 10,000, RG = 8.0 Ω (7.87 Ω 1% standard value). At this gain, wiring resistance becomes critical - use Kelvin connections and avoid sockets to maintain accuracy. The INA126PA datasheet specifies gain error up to ±1% at G = 100 and ±0.18% at G = 5.
Does the INA126PA require external trimming for offset voltage in precision applications?
No, the INA126PA does not require external offset trimming in most applications. Its maximum input offset voltage is 250 μV (with typical 150 μV for the PA grade), and offset drift is limited to 3 μV/°C - sufficient for 0.1% accuracy in G = 100 configurations over –40°C to +85°C. Section 7.2.2.2 of the INA126PA datasheet shows an optional trim circuit using an OPA237 buffer and REF200 current source only if sub-10 μV residual offset is required.
How should the REF pin (pin 5) of the INA126PA be connected for optimal common-mode rejection?
The REF pin of the INA126PA must be driven by a low-impedance source - ideally ≤8 Ω - to maintain specified CMRR. In most cases, connect REF directly to system ground or to a precision voltage reference (e.g., REF5025) buffered with a unity-gain op-amp. Avoid series resistors or long traces; even 8 Ω resistance degrades CMRR from 74 dB to ~80 dB. The INA126PA output voltage is VO = G × (V+IN – V–IN) + VREF, so REF defines the output DC level.
Can the INA126PA operate from a single 5V supply, and what are the input/output limitations?
Yes, the INA126PA supports single-supply operation from 2.7V to 36V. With VS = +5V/0V, the input common-mode range is limited to approximately –0.5V to +3.5V (see Figure 5-7), and output swing is typically 0.75V to 4.25V. To maximize dynamic range, bias the REF pin at 2.5V (midsupply) using a low-impedance divider or reference. The INA126PA maintains 175 μA IQ and 35 nV/√Hz noise under these conditions, confirmed in Section 5.3 and Figure 5-7 of the datasheet.
What is the purpose of the Sense pins in the INA126PA, and are they present on this device?
The INA126PA does not have Sense pins - those are exclusive to the dual-channel INA2126. The INA126PA uses a two-op-amp architecture without internal feedback-sense nodes. Its output (pin 6) connects directly to the load; no external Sense connection is required or supported. Confusion may arise because the INA2126 datasheet (same document) describes SenseA/SenseB for channel-level feedback - but these pins do not exist on the INA126PA's 8-pin PDIP footprint.
INA126PA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
INA126PA FAQ
1.How can I place an order for INA126PA through Aetrix?
Please submit a Request for Quotation (RFQ) for INA126PA 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 INA126PA reliable?
The price and inventory of INA126PA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA126PA is usually 5 days.
3.What payment methods are accepted for INA126PA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA126PA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA126PA?
INA126PA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA126PA 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 INA126PA?
For technical support, including INA126PA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA126PA requirements.
6.How does Aetrix verify that INA126PA is sourced from the original manufacturer or authorized distributors?
All INA126PA 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 INA126PA meets industry standards.
7.What is the process for return or replacement of INA126PA?
All INA126PA units undergo pre-shipment inspection (PSI). If there is an issue with INA126PA, 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 INA126PA part is unused and in its original packaging.
Return procedure for INA126PA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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