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Texas Instruments OPA2131UAG4
- Part No.:
- OPA2131UAG4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA2131UAG4.pdf
- Description:
- IC OPAMP JFET 2 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,452
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Product details
Overview
OPA2131UAG4 from Texas Instruments is a dual-channel, FET-input operational amplifier optimized for precision analog signal conditioning in instrumentation and data acquisition systems. It delivers 750 μV max input offset voltage, 10 V/μs slew rate, 4 MHz gain bandwidth, ±4.5 V to ±18 V supply range, and 50 pA max input bias current - enabling high-accuracy DC-coupled amplification in ECG front-ends and flow transmitter sensor interfaces.
For engineers reviewing the OPA2131UAG4 datasheet, OPA2131UAG4 pinout, OPA2131UAG4 application, or OPA2131UAG4 equivalent, this page provides verified electrical specifications, SOIC-8 package terminal mapping, real-world use cases in medical and industrial sensing, and two validated alternative op amps with documented functional trade-offs.
Technical Context
The OPA2131UAG4 implements a JFET-input stage with laser-trimmed input offset, delivering stable DC performance across –40°C to +85°C ambient. Its unity-gain stability, low 15 nV/√Hz input voltage noise at 1 kHz, and robust capacitive load drive (up to 300 pF) support precision transimpedance and active filter designs without external compensation.
Both amplifiers in the dual package operate independently: overdrive or short-circuit on one channel does not affect the other's output phase or common-mode behavior. The device avoids input-stage phase reversal - a known failure mode in unguarded FET op amps - making it suitable for voltage-follower configurations in closed-loop control paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Offset Voltage | ±750 μV max - ensures ≤0.75 mV DC error in unity-gain buffers at room temperature. |
| Slew Rate | 10 V/μs - supports 10 Vpp signals up to ~1.6 MHz before slew-induced distortion dominates. |
| Gain Bandwidth Product | 4 MHz - enables stable G = 100 amplification up to 40 kHz with predictable phase margin. |
| Input Bias Current | ±50 pA max - minimizes voltage drop across high-impedance sensor sources (e.g., pH electrodes, piezoresistive bridges). |
| Supply Range | ±4.5 V to ±18 V - accommodates legacy ±15 V rails and modern low-voltage industrial systems down to ±4.5 V. |
| Common-Mode Rejection | 70 dB min - rejects >90% of 60 Hz interference when used in differential sensor interfaces. |
| Quiescent Current | ±1.75 mA per amplifier - balances low power consumption with dynamic performance in battery-backed DAQ modules. |
Pinout & Package
OPA2131UAG4 is housed in an 8-pin SOIC (D) surface-mount package with standard industry pinout. Thermal resistance is RθJA = 150°C/W, supporting operation up to +85°C ambient without forced airflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT A | Amplifier A output - drives loads ≥2 kΩ; swings within 2.5 V of each rail under full load. |
| 2 | –IN A | Inverting input, channel A - high-impedance node (1012 Ω || 4.3 pF); sensitive to PCB leakage and guarding. |
| 3 | +IN A | Noninverting input, channel A - same impedance as –IN A; used for reference-biased sensor interfaces. |
| 4 | V– | Negative supply - must be decoupled with ≥10 nF ceramic capacitor near the pin to suppress PSRR degradation. |
| 5 | +IN B | Noninverting input, channel B - electrically isolated from channel A; enables dual-sensor synchronous sampling. |
| 6 | –IN B | Inverting input, channel B - independent bias current path; no crosstalk with channel A inputs. |
| 7 | OUT B | Amplifier B output - identical AC/DC specs to OUT A; supports dual-path signal conditioning without inter-channel coupling. |
| 8 | V+ | Positive supply - shares same decoupling requirement as V–; supplies both amplifiers from single rail pair. |
Key Features
| Feature | Design Value |
|---|---|
| FET input stage | 50 pA max input bias current enables direct interfacing with megohm-range sensors without significant DC error. |
| Laser-trimmed offset | ±750 μV max input offset voltage eliminates need for external nulling circuitry in production-grade medical devices. |
| Unity-gain stable | No external compensation required - simplifies layout for gain-of-1 buffers and active filters with G ≤ 100. |
| No phase reversal | Guaranteed output polarity integrity even when input common-mode exceeds (V–)+3 V or (V+)-3.5 V limits. |
| Independent dual channels | Zero crosstalk between amplifiers allows simultaneous processing of two isolated sensor signals on one die. |
Applications
| ECG Front-End Amplifier | Flow Transmitter Signal Conditioning |
|---|---|
|
Use Scenario: Amplifying microvolt-level biopotential signals from Ag/AgCl electrodes while rejecting 50/60 Hz mains interference. IC Role / Device Role / Timing Role: Dual-channel instrumentation amplifier first stage - one channel for lead I, second for lead II - with matched DC specs and independent power domains. Use Value: 70 dB CMRR and 15 nV/√Hz input noise preserve diagnostic SNR; ±750 μV offset ensures baseline stability across patient temperature shifts. |
Use Scenario: Converting low-level current output (4–20 mA) from Coriolis or magnetic flow sensors into calibrated voltage for ADC input. IC Role / Device Role / Timing Role: Precision current-to-voltage converter and anti-aliasing filter driver - leveraging low IB to avoid gain error in high-R shunt networks. Use Value: 50 pA max input bias current prevents >0.1% gain error in 100 kΩ shunt resistors; 10 V/μs slew rate handles transient flow spikes without clipping. |
| Data Acquisition Channel | Lab Instrumentation Buffer |
|
Use Scenario: Isolating and scaling analog outputs from thermocouples, RTDs, or strain gauges before multiplexing into a 16-bit SAR ADC. IC Role / Device Role / Timing Role: Rail-to-rail input buffer with programmable gain - configured as noninverting amplifier (G = 1 to 100) using precision metal-film resistors. Use Value: 4 MHz GBW supports 100 kHz settling for 16-bit accuracy; ±1.75 mA quiescent current enables multi-channel DAQ with <5 mW/channel power budget. |
Use Scenario: Driving long cables or reactive loads (e.g., oscilloscope inputs, relay coils) from benchtop multimeters and function generators. IC Role / Device Role / Timing Role: Low-distortion unity-gain buffer - compensating for source impedance mismatch and cable capacitance-induced peaking. Use Value: Excellent capacitive load drive (stable with 300 pF) eliminates ringing on 1-m coaxial cables; 0.0008% THD+N preserves signal fidelity at 1 kHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision FET-input op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA2132UA | Lower 12 nV/√Hz noise at 1 kHz, 8 MHz GBW, but 1.8 mA IQ per channel - 15% higher supply current than OPA2131UAG4. | Better suited for wideband audio preamps where noise bandwidth exceeds 100 kHz; less optimal for battery-powered DAQ with tight thermal constraints. | Select OPA2132UA only when >2× bandwidth or <20% lower noise is required - otherwise OPA2131UAG4 offers better cost/power/performance balance. |
| TL072CDR | Higher 15 mV max VOS, 200 pA max IB, 3 MHz GBW, and no laser trimming - significantly looser DC specs and higher drift. | Acceptable for non-critical AC-coupled applications (e.g., audio mixing), but unsuitable for DC-stable medical or sensor front-ends requiring sub-mV accuracy. | Choose TL072CDR only for cost-sensitive, non-precision designs where offset drift and noise are secondary to BOM cost - not a functional replacement for OPA2131UAG4 in precision roles. |
Compared with OPA2132UA and TL072CDR, the OPA2131UAG4 uniquely balances low input bias current (≤50 pA), tight offset (≤750 μV), and moderate power (≤1.75 mA), making it the optimal choice for industrial and medical DAQ where DC accuracy, sensor compatibility, and thermal headroom are co-constrained.
Availability
OPA2131UAG4 is available at Aetrix Electronics and suitable for electrocardiogram (ECG) monitors, flow transmitter calibration modules, and portable data acquisition systems requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for OPA2131UAG4 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 over 50 years of innovation in precision op amps and signal chain solutions.
The OPAx131 product line was designed specifically for general-purpose, high-accuracy analog signal conditioning in cost-sensitive instrumentation - prioritizing FET-input performance, industry-standard SOIC packaging, and broad operating temperature support.
FAQ
What is the maximum operating temperature for the OPA2131UAG4?
The OPA2131UAG4 is rated for operation from –40°C to +85°C ambient temperature. This range is specified in the Recommended Operating Conditions table and validated across production lots. The device's SOIC-8 package has a junction-to-ambient thermal resistance of 150°C/W, so internal die temperature remains within safe limits (<125°C) under typical PCB layouts with modest copper area and no forced airflow.
Does the OPA2131UAG4 require external compensation for unity-gain stability?
No, the OPA2131UAG4 is internally compensated for unity-gain stability. It maintains phase margin >45° at G = 1 across all process corners and temperatures, eliminating the need for external compensation capacitors. This is confirmed in Section 6.1 of the datasheet, which states "The OPAx131 series op amps are unity-gain stable" and demonstrates stable step response in Figure 5-12.
What is the input common-mode voltage range for the OPA2131UAG4?
The input common-mode voltage range for the OPA2131UAG4 is (V–) + 3 V to (V+) – 3.5 V. For example, with ±15 V supplies, inputs must stay between –12 V and +11.5 V. This specification is explicitly listed in Table 5-6 under "INPUT VOLTAGE - VCM" and is guaranteed over the full –40°C to +85°C operating range.
Can the OPA2131UAG4 drive capacitive loads without oscillation?
Yes, the OPA2131UAG4 is characterized for stable operation with up to 300 pF capacitive load, as shown in Figure 5-12 (small-signal step response) and Figure 5-15 (overshoot vs. load capacitance). It achieves this via internal compensation and output stage design - no external isolation resistor is required for typical cable or ADC input capacitance.
Is the OPA2131UAG4 pin-compatible with other dual op amps in SOIC-8 packages?
The OPA2131UAG4 uses the industry-standard dual op amp pinout (pin 1 = OUT A, pin 2 = –IN A, pin 3 = +IN A, pin 4 = V–, pin 5 = +IN B, pin 6 = –IN B, pin 7 = OUT B, pin 8 = V+), matching TI's OPA2132, OPA227, and legacy TL072. However, functional equivalence requires verification of offset, noise, and supply current - e.g., TL072 lacks laser trimming and has higher VOS/IB.
OPA2131UAG4 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:
- J-FET
- Number of Circuits:
- 2
- Output Type:
- -
- Slew Rate:
- 10V/µs
- Gain Bandwidth Product:
- 4 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 5 pA
- Voltage - Input Offset:
- 200 µV
- Current - Supply:
- 1.5mA (x2 Channels)
- Current - Output / Channel:
- 25 mA
- Voltage - Supply Span (Min):
- 9 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
OPA2131UAG4 FAQ
1.How can I place an order for OPA2131UAG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA2131UAG4 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 OPA2131UAG4 reliable?
The price and inventory of OPA2131UAG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA2131UAG4 is usually 5 days.
3.What payment methods are accepted for OPA2131UAG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA2131UAG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA2131UAG4?
OPA2131UAG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA2131UAG4 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 OPA2131UAG4?
For technical support, including OPA2131UAG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA2131UAG4 requirements.
6.How does Aetrix verify that OPA2131UAG4 is sourced from the original manufacturer or authorized distributors?
All OPA2131UAG4 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 OPA2131UAG4 meets industry standards.
7.What is the process for return or replacement of OPA2131UAG4?
All OPA2131UAG4 units undergo pre-shipment inspection (PSI). If there is an issue with OPA2131UAG4, 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 OPA2131UAG4 part is unused and in its original packaging.
Return procedure for OPA2131UAG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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