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Texas Instruments OPA2131UA
- Part No.:
- OPA2131UA
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA2131UA.pdf
- Description:
- IC OPAMP JFET 2 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,572
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Product details
Overview
OPA2131UA from Texas Instruments is a dual-channel, FET-input operational amplifier in an 8-pin SOIC package, delivering 4MHz gain bandwidth, 10V/μs slew rate, and ±750μV maximum input offset voltage across –40°C to +85°C. It operates from ±4.5V to ±18V supplies and drives capacitive loads robustly-used in precision ECG front-ends and industrial flow transmitter signal conditioning.
For engineers reviewing the OPA2131UA datasheet, OPA2131UA pinout, OPA2131UA application, or OPA2131UA equivalent, this page provides verified electrical specs, dual-amplifier channel isolation behavior, SOIC-8 thermal metrics (RθJA = 150°C/W), and validated alternatives for low-bias-current analog signal chains requiring stable DC accuracy and wide dynamic range.
Technical Context
The OPA2131UA implements fully independent dual amplifiers with no crosstalk-each channel features laser-trimmed input offset voltage (±1mV max) and ultra-low input bias current (±50pA max). Its FET-input architecture eliminates base-current errors common in bipolar op amps, enabling high-impedance sensor interfacing without significant loading.
It is unity-gain stable and immune to output phase reversal when common-mode voltage exceeds rails-a known failure mode in legacy FET op amps. The device supports rail-to-rail output swing within 2.5V of each supply and maintains >70dB CMRR over –12V to +11.5V common-mode range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Bandwidth Product | 4 MHz - Enables stable closed-loop operation up to 400 kHz at G = 10 without compensation. |
| Slew Rate | 10 V/μs - Supports fast transient response in active filters and precision DAC buffers. |
| Input Offset Voltage | ±750 μV max (TA = –40°C to +85°C) - Ensures <1 LSB error in 12-bit systems with ±10V full-scale. |
| Input Bias Current | ±50 pA max - Allows use with >100 MΩ source impedances without significant DC error. |
| Supply Voltage Range | ±4.5 V to ±18 V - Compatible with legacy industrial ±5V, ±12V, and ±15V power rails. |
| Common-Mode Rejection | 70 dB min (–12V ≤ VCM ≤ 11.5V) - Maintains accuracy in noisy industrial environments with ground shifts. |
| Quiescent Current | ±1.75 mA per amplifier - Enables dual-channel precision amplification within 3.5 mA total supply budget. |
Pinout & Package
OPA2131UA is housed in an industry-standard 8-pin SOIC (D package), surface-mount package with 1.27 mm pitch and JEDEC MS-012AC footprint. Thermal resistance is RθJA = 150°C/W and RθJC(top) = 52.3°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OUT A (Pin 1) | Output | Amplifier A output; capable of ±20 mA short-circuit current and ±12 V swing into 2 kΩ load. |
| –IN A (Pin 2) | Input | Inverting input for Channel A; high-impedance FET node with ±50 pA bias current. |
| +IN A (Pin 3) | Input | Noninverting input for Channel A; matched to –IN A for optimal CMRR performance. |
| V– (Pin 4) | Power | Negative supply rail connection; must be bypassed with ≥10 nF ceramic capacitor near pin. |
| +IN B (Pin 5) | Input | Noninverting input for Channel B; electrically isolated from Channel A with no crosstalk. |
| –IN B (Pin 6) | Input | Inverting input for Channel B; independent bias current path ensures dual-channel integrity. |
| OUT B (Pin 7) | Output | Amplifier B output; identical AC/DC specs to OUT A; supports simultaneous dual-signal processing. |
| V+ (Pin 8) | Power | Positive supply rail connection; requires local 10 nF ceramic decoupling for stability. |
Key Features
| Feature | Design Value |
|---|---|
| FET input stage | Enables <50 pA input bias current-critical for photodiode transimpedance and high-Z sensor interfaces. |
| Laser-trimmed offset | ±750 μV max over temperature eliminates need for external nulling in production systems. |
| No phase reversal | Prevents catastrophic output inversion during input overdrive-essential in closed-loop control and ECG monitoring. |
| Capacitive load drive | Stable with ≥300 pF load-simplifies anti-alias filter design without external isolation resistors. |
| Independent dual channels | Zero inter-channel crosstalk allows simultaneous use in differential pair or dual-path signal chains. |
Applications
| ECG Front-End Amplifier | Industrial Flow Transmitter |
|---|---|
|
Use Scenario: Amplifying microvolt-level biopotential signals from Ag/AgCl electrodes with 50/60 Hz notch filtering and baseline drift correction. IC Role / Device Role / Timing Role: Dual-channel OPA2131UA configures as instrumentation amplifier first stage (A) and right-leg drive buffer (B), leveraging matched FET inputs for ultra-low input current and offset. Use Value: ±50 pA input bias prevents electrode polarization; ±750 μV offset avoids saturation in 1000× gain stages; 4 MHz GBW supports digital notch implementation. |
Use Scenario: Conditioning analog output from Coriolis or magnetic flow sensors in hazardous-area transmitters with 4–20 mA loop power constraints. IC Role / Device Role / Timing Role: OPA2131UA serves as low-drift sensor excitation buffer (Channel A) and ratiometric signal amplifier (Channel B), operating from ±15 V isolated supplies. Use Value: ±4.5 V to ±18 V supply range matches legacy 4–20 mA loop power; 10 V/μs slew rate handles fast flow transients; 70 dB CMRR rejects common-mode noise on long sensor cables. |
| Data Acquisition Channel | Lab Instrumentation Signal Chain |
|
Use Scenario: Precision DC-coupled input stage in 16-bit data acquisition modules handling thermocouple, RTD, and strain gauge signals. IC Role / Device Role / Timing Role: OPA2131UA used in dual configuration: one channel for programmable-gain amplification, second for reference buffer-both sharing same thermal environment. Use Value: Laser-trimmed offset drift (±10 μV/°C) ensures <0.01% FS error over 0–70°C ambient; SOIC-8 package enables compact layout with matched trace lengths. |
Use Scenario: Low-noise preamplifier and active filter section in benchtop oscilloscopes, spectrum analyzers, and arbitrary waveform generators. IC Role / Device Role / Timing Role: OPA2131UA implements 2nd-order low-pass filter (Figure 6-1) and DC-coupled gain stage, exploiting unity-gain stability and 4 MHz bandwidth. Use Value: 15 nV/√Hz input voltage noise at 1 kHz minimizes added noise floor; excellent capacitive load drive simplifies PCB layout with integrated filter caps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual FET-input operational amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA2132UA | Lower input bias current (±10 pA typ), higher GBW (8 MHz), but higher quiescent current (2.2 mA/ch). | Better for ultra-high-Z sources (>1 GΩ) and wider-bandwidth filters; less suitable for low-power DAQ. | Select OPA2132UA when sub-10 pA bias and >5 MHz bandwidth are required; accept 25% higher supply current. |
| TL072CDR | Higher input bias current (±200 pA), lower GBW (3 MHz), no laser trimming (±10 mV VOS), but lower cost and wider temp range (–40°C to 125°C). | Acceptable for non-critical audio and general-purpose buffering where offset drift is not constrained. | Choose TL072CDR only for cost-sensitive, non-precision applications; avoid in medical or metrology-grade designs. |
Compared with OPA2131UA, OPA2132UA offers superior bandwidth and bias current for demanding sensor interfaces, while TL072CDR trades precision for cost and temperature range-neither is pin-compatible, requiring layout revision.
Availability
OPA2131UA is available at Aetrix Electronics and suitable for ECG front-end amplifiers, industrial flow transmitters, and precision data acquisition systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for OPA2131UA 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 op amp design and manufacturing reliability.
The OPAx131 series was developed for cost-effective, high-accuracy analog signal conditioning in industrial, medical, and test equipment-emphasizing low input bias, stable offset, and robust capacitive load drive in standard packages.
FAQ
What is the maximum operating temperature range for the OPA2131UA?
The OPA2131UA is rated for operation from –40°C to +85°C ambient temperature, as confirmed in the Recommended Operating Conditions table (Section 5.2) and Package Option Addendum. This range applies specifically to the /B suffix variant (e.g., OPA2131UA.B and OPA2131UA/2K5.B), which matches the ordering row provided. The OPA2131UA part number itself supports both –40°C to +85°C and –55°C to +125°C variants, but the /B marking denotes the industrial temperature grade.
Does the OPA2131UA require external offset nulling circuitry?
No, the OPA2131UA does not require external offset nulling. Its input offset voltage is laser-trimmed to ±750 μV maximum over –40°C to +85°C, and input offset voltage drift is limited to ±10 μV/°C. These specifications are verified in Section 5.6 Electrical Characteristics and explicitly stated in Section 6.1.1 Offset Voltage Trim, confirming that user adjustment is unnecessary in production designs.
Is the OPA2131UA unity-gain stable and safe to use in voltage-follower configurations?
Yes, the OPA2131UA is unity-gain stable and explicitly designed for voltage-follower use. Section 6.1 Application Information states it is "unity-gain stable" and highlights immunity to output phase reversal-a critical failure mode in FET-input op amps when input common-mode voltage exceeds rails. This makes the OPA2131UA safe for direct buffer applications in ECG and sensor signal chains without risk of latch-up or oscillation.
What is the thermal resistance (RθJA) of the OPA2131UA in its SOIC-8 package?
The junction-to-ambient thermal resistance (RθJA) for the OPA2131UA in the D (SOIC-8) package is 150°C/W, as specified in Section 5.4 Thermal Information – OPA2131. This value assumes standard JEDEC 2-layer board conditions and is consistent across all OPA2131UA variants, including tape-and-reel formats like OPA2131UA/2K5.B.
Can the OPA2131UA drive a 1000 pF capacitive load without instability?
The OPA2131UA is characterized for stable operation with ≥300 pF capacitive loads (Figure 5-15), but driving 1000 pF requires external isolation. Section 6.1 notes "excellent capacitive load drive," and Figure 5-15 shows increasing overshoot beyond 300 pF. For 1000 pF, a series resistor (≥100 Ω) between output and load is recommended-verified in typical application guidance and small-signal step response data (Figure 5-12).
OPA2131UA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- 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
OPA2131UA FAQ
1.How can I place an order for OPA2131UA through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA2131UA 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 OPA2131UA reliable?
The price and inventory of OPA2131UA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA2131UA is usually 5 days.
3.What payment methods are accepted for OPA2131UA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA2131UA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA2131UA?
OPA2131UA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA2131UA 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 OPA2131UA?
For technical support, including OPA2131UA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA2131UA requirements.
6.How does Aetrix verify that OPA2131UA is sourced from the original manufacturer or authorized distributors?
All OPA2131UA 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 OPA2131UA meets industry standards.
7.What is the process for return or replacement of OPA2131UA?
All OPA2131UA units undergo pre-shipment inspection (PSI). If there is an issue with OPA2131UA, 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 OPA2131UA part is unused and in its original packaging.
Return procedure for OPA2131UA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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