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Texas Instruments OPA656UB/2K5
- Part No.:
- OPA656UB/2K5
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA656UB/2K5.pdf
- Description:
- IC VOLTAGE FEEDBACK 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,829
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Product details
Overview
OPA656UB/2K5 from Texas Instruments is a unity-gain stable, FET-input voltage-feedback operational amplifier optimized for ultra-low-noise transimpedance and high-speed data acquisition front-ends. It delivers 550MHz unity-gain bandwidth, 6nV/√Hz input voltage noise, and ±2pA input bias current, enabling precision optical signal conditioning in photodiode-based systems operating from –40°C to +85°C.
For engineers reviewing the OPA656UB/2K5 datasheet, OPA656UB/2K5 pinout, OPA656UB/2K5 application, or OPA656UB/2K5 equivalent, this page provides verified technical context, package-specific pin functions, real-world application mappings, and validated alternative options for optical test equipment, medical analyzers, and high-bandwidth DAQ systems.
Technical Context
The OPA656UB/2K5 uses a low-noise JFET input stage on a high-speed complementary bipolar process, achieving unity-gain stability without external compensation. Its 230MHz gain-bandwidth product and 150MHz large-signal bandwidth (2VPP) support wideband noninverting and inverting configurations with minimal phase shift up to 100MHz.
It operates from ±5V (8V–12V total supply), features 80dB CMRR and 72dB +PSRR at 25°C, and maintains dc precision via trimmed offset voltage (±0.6mV max) and drift (±6μV/°C max) in its high-grade UB variant - critical for stable transimpedance gain in optical time-domain reflectometry and active probe designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Unity-gain bandwidth | 550MHz - enables stable buffer operation up to VHF range without peaking or oscillation |
| Gain-bandwidth product | 230MHz - sets maximum closed-loop bandwidth vs gain (e.g., 46MHz at G=5) |
| Input voltage noise | 6nV/√Hz - dominates transimpedance noise floor below 10MHz, minimizing integrated output noise |
| Input bias current | ±2pA max - preserves high-impedance photodiode node integrity and reduces dark-current error |
| Large-signal bandwidth | 150MHz at 2VPP - supports fast pulse acquisition in oscilloscope front-ends and OTDR receivers |
| Supply voltage range | ±5V nominal (8V–12V total) - compatible with standard dual-rail lab supplies and isolated DC/DC modules |
| Input offset voltage | ±0.6mV max (high-grade UB) - ensures <0.1% gain error in 100kΩ transimpedance configurations |
Pinout & Package
The OPA656UB/2K5 is supplied in an 8-pin SOIC (D package), 4.9mm × 6mm body size, with exposed pad not present and no thermal slug. Pin 1, 5, and 8 are NC (no internal connection); functional pins follow industry-standard op-amp layout for drop-in compatibility in existing layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN+ | Noninverting input | High-impedance JFET node; connects to photodiode cathode or signal source in transimpedance mode |
| VIN− | Inverting input | Feedback node; ties directly to RF in TIA or forms summing junction in inverting amplifiers |
| VOUT | Amplifier output | Capable of ±3.5V swing into 100Ω; requires series resistor for >50pF capacitive loads per Figure 6-7 |
| +VS | Positive power supply | Accepts +5V (±5V system); decoupling with 6.8μF + 0.1μF recommended per Figure 8-1 |
| −VS | Negative power supply | Accepts −5V (±5V system); separate ground plane routing advised to minimize PSRR degradation |
Key Features
| Feature | Design Value |
|---|---|
| Unity-gain stable architecture | No external compensation required - simplifies layout and eliminates stability tuning in 1× buffers |
| JFET input stage | 10¹²Ω || 0.4pF input impedance - minimizes loading on high-Z photodiodes and piezoelectric sensors |
| Low harmonic distortion | –100dBc HD3 at 5MHz (RL = 200Ω) - preserves signal fidelity in spectrum analyzer front-ends |
| Industrial temperature range | –40°C to +85°C operation - qualified for medical analyzers and field-deployable test equipment |
| ESD robustness | ±2000V HBM - withstands handling in production environments without special ESD protocols |
Applications
| Optical Time-Domain Reflectometry (OTDR) | Medical Laser Blood Analyzers |
|---|---|
Use Scenario: Detecting weak backscattered light pulses from fiber-optic cables over distances up to 120km. IC Role / Device Role / Timing Role: Transimpedance amplifier converting photodiode current to voltage with 100kΩ gain and 4MHz bandwidth. Use Value: 6nV/√Hz input noise enables sub-picoamp sensitivity; 150MHz large-signal BW captures nanosecond-scale pulse edges. |
Use Scenario: Amplifying low-level photocurrent from hemoglobin absorption measurements in flow cytometry. IC Role / Device Role / Timing Role: Precision current-to-voltage converter in analog front-end before 16-bit ADC sampling at 1MSps. Use Value: ±0.6mV max VOS ensures <0.05% baseline drift across 0–45°C ambient; ±2pA IB avoids diode leakage-induced offset. |
| Active Oscilloscope Probes | High-Speed Data Acquisition Front-Ends |
Use Scenario: 10× passive/active probe with 1GHz analog bandwidth and 1MΩ || 12pF input impedance. IC Role / Device Role / Timing Role: Unity-gain buffer isolating scope input from DUT; driven by low-capacitance PCB trace. Use Value: 550MHz unity-gain BW achieves flat response to 500MHz; 1.3ns rise time meets 1GHz probe specification. |
Use Scenario: Digitizing transient signals from particle detectors or radar receivers at 250MSPS. IC Role / Device Role / Timing Role: Wideband driver for ADC input, configured as gain-of-2 noninverting amplifier. Use Value: 230MHz GBW supports 115MHz closed-loop BW at G=2; –80dBc HD2 at 5MHz prevents aliasing in undersampled systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed, low-noise op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA814IDBVR | 250MHz GBW, 5.3nV/√Hz noise, 750V/μs slew rate; requires minimum gain ≥1 | Better noise/speed trade-off for G≥2; less suitable for unity-gain TIA | Select when higher slew rate and lower noise justify tighter gain constraints |
| OPA659UB/2K5 | 350MHz GBW, 8.9nV/√Hz noise, 2550V/μs slew rate; minimum stable gain = 7 V/V | Superior speed for G≥7; unsuitable for unity-gain or low-gain buffers | Choose only for fixed-gain ≥7 signal chains where 550MHz UGBW is unnecessary |
Compared with OPA656UB/2K5, OPA814 offers lower noise and higher slew rate but sacrifices unity-gain stability, while OPA659 delivers extreme speed at the cost of mandatory gain ≥7 - making OPA656UB/2K5 uniquely balanced for transimpedance and unity-gain buffer roles requiring both precision and bandwidth.
Availability
OPA656UB/2K5 is available at Aetrix Electronics and suitable for optical time-domain reflectometry, medical laser analyzers, and high-speed data acquisition systems requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for OPA656UB/2K5 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 op-amp innovation and broad automotive, industrial, and communications portfolio coverage.
The OPA656UB/2K5 belongs to TI's high-speed precision op-amp product line, engineered specifically for transimpedance amplification and test/measurement front-ends where unity-gain stability, ultra-low noise, and dc accuracy must coexist.
FAQ
What is the maximum supply voltage for the OPA656UB/2K5?
The OPA656UB/2K5 has an absolute maximum supply voltage of ±6.5V (13V total), but its recommended operating range is ±5V (10V total) with a minimum of ±4V (8V total). Operation beyond ±6V risks permanent damage per Section 6.1 Absolute Maximum Ratings. The OPA656UB/2K5 is fully specified and characterized at ±5V, where it delivers optimal noise, bandwidth, and distortion performance.
Does the OPA656UB/2K5 require external compensation for unity-gain stability?
No, the OPA656UB/2K5 is internally compensated for unity-gain stability and does not require external compensation components. Its design guarantees stable operation with closed-loop gains ≥1 V/V, including the unity-gain follower configuration. This is confirmed in Section 1 Features ("Unity-gain stable") and Section 7.1 Overview, eliminating layout risk in buffer and transimpedance applications.
What is the input bias current specification for the OPA656UB/2K5?
The OPA656UB/2K5 specifies input bias current as ±2pA maximum at 25°C (Section 6.5 Electrical Characteristics), with ±1250pA maximum over the full –40°C to +85°C industrial temperature range (Section 6.6 High Grade DC Specifications). This ultra-low IB enables direct interfacing with high-impedance photodiodes and piezoelectric sensors without significant dc error.
Can the OPA656UB/2K5 be used in single-supply applications?
Yes, the OPA656UB/2K5 supports single-supply operation, as stated in Section 7.3 Device Functional Modes: "The OPA656 can be operated on both single and dual supplies." For single-supply use, the input common-mode range extends to within 2.1V of the negative rail (Section 6.5), requiring proper level-shifting and biasing - e.g., mid-supply reference for VIN+ in noninverting configurations.
What package type is used for the OPA656UB/2K5 orderable part number?
The OPA656UB/2K5 is packaged in an 8-pin SOIC (D package), measuring 4.9mm × 6mm, as documented in the Package Information table and Section 11 Mechanical, Packaging, and Orderable Information. This surface-mount package is compatible with standard reflow profiles and widely supported in automated assembly lines for industrial and test equipment manufacturing.
OPA656UB/2K5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Voltage Feedback
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 295V/µs
- Gain Bandwidth Product:
- 230 MHz
- -3db Bandwidth:
- 500 MHz
- Current - Input Bias:
- 1 pA
- Voltage - Input Offset:
- 250 µV
- Current - Supply:
- 14mA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 8 V
- Voltage - Supply Span (Max):
- 12 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
OPA656UB/2K5 FAQ
1.How can I place an order for OPA656UB/2K5 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA656UB/2K5 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 OPA656UB/2K5 reliable?
The price and inventory of OPA656UB/2K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA656UB/2K5 is usually 5 days.
3.What payment methods are accepted for OPA656UB/2K5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA656UB/2K5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA656UB/2K5?
OPA656UB/2K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA656UB/2K5 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 OPA656UB/2K5?
For technical support, including OPA656UB/2K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA656UB/2K5 requirements.
6.How does Aetrix verify that OPA656UB/2K5 is sourced from the original manufacturer or authorized distributors?
All OPA656UB/2K5 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 OPA656UB/2K5 meets industry standards.
7.What is the process for return or replacement of OPA656UB/2K5?
All OPA656UB/2K5 units undergo pre-shipment inspection (PSI). If there is an issue with OPA656UB/2K5, 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 OPA656UB/2K5 part is unused and in its original packaging.
Return procedure for OPA656UB/2K5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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