My Inquiry
My Account
Texas Instruments OPA656U
- Part No.:
- OPA656U
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA656U.pdf
- Description:
- IC VOLTAGE FEEDBACK 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,212
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
OPA656U from Texas Instruments is a unity-gain stable, FET-input voltage-feedback operational amplifier optimized for high-dynamic-range transimpedance and high-speed data acquisition front-ends. It delivers 550MHz unity-gain bandwidth, 6nV/√Hz input voltage noise, 2pA input bias current, and ±600μV max input offset voltage across –40°C to +85°C - enabling precision optical signal conditioning in oscilloscope front-ends and OTDR modules.
For engineers reviewing the OPA656U datasheet, OPA656U pinout, OPA656U application, or OPA656U equivalent, this page provides verified electrical specifications, SOIC-8 and SOT-23-5 package mapping, confirmed transimpedance design parameters, thermal resistance values (RθJA = 123°C/W for D package), and two validated alternative op-amps with documented performance trade-offs.
Technical Context
The OPA656U employs a low-noise JFET input stage on a high-speed complementary bipolar process, achieving ultra-low input voltage noise (6nV/√Hz) and high input impedance (>10¹² Ω || 0.4 pF) critical for photodiode transimpedance amplification. Its unity-gain stability and 230MHz gain-bandwidth product support wideband noninverting and inverting configurations without external compensation.
It operates from ±5V (8V–12V total supply), features 400V/μs slew rate, 130MHz large-signal bandwidth (2VPP), and maintains <±2.6mV input offset voltage over industrial temperature range. Input bias current remains ≤±5pA at 85°C, supporting low-leakage optical sensor interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Unity-gain bandwidth | 550MHz - enables direct buffering of >200MHz analog signals without gain peaking or instability |
| Gain-bandwidth product | 230MHz - supports stable closed-loop gains ≥1 V/V while preserving >50MHz 0.1-dB flatness |
| Input voltage noise | 6nV/√Hz - minimizes integrated noise in transimpedance applications with high RF values (e.g., 100kΩ) |
| Input bias current | 2pA (max) - ensures negligible DC error in high-impedance photodiode or active probe inputs |
| Input offset voltage | ±0.6mV (max, high-grade spec) - enables sub-mV precision in DC-coupled test equipment front-ends |
| Slew rate | 400V/μs - sustains clean 2VPP output swings up to 130MHz without slewing distortion |
| Supply voltage range | ±5V (8V–12V total) - compatible with standard dual-rail lab instrumentation power rails |
Pinout & Package
The OPA656U is available in two surface-mount packages: 8-pin SOIC (D package, 4.9mm × 6mm) and 5-pin SOT-23 (DBV package, 2.9mm × 2.8mm). Both variants share identical pin functions and electrical specifications.
| 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 configuration; requires minimal parasitic capacitance |
| VOUT | Amplifier output | Capable of ±3.5V swing into 100Ω; drives 50Ω test equipment or ADC input with controlled termination |
| +VS | Positive power supply | Accepts +5V nominal; must be decoupled with 6.8μF + 0.1μF per datasheet layout guidelines |
| −VS | Negative power supply | Accepts −5V nominal; shares same decoupling requirements as +VS for PSRR optimization |
| NC | No-connect | Pins 1, 5, 8 in SOIC (D) package - must remain unconnected; no internal function |
Key Features
| Feature | Design Value |
|---|---|
| Unity-gain stable architecture | Eliminates need for external compensation components in buffer or gain-of-1 configurations |
| Low input voltage noise density | 6nV/√Hz dominates system noise floor only above ~1MHz in 100kΩ TIA designs |
| JFET input stage | Delivers >10¹² Ω input impedance - essential for minimizing loading on high-Z photodiodes and passive probes |
| Industrial temperature range | Specified from –40°C to +85°C - supports deployment in benchtop test equipment and field-deployable OTDR units |
| High PSRR | +PSRR = 72dB (typ), –PSRR = 56dB (typ) - reduces sensitivity to supply rail noise in mixed-signal systems |
Applications
| Oscilloscope Front-End | Optical Time-Domain Reflectometry (OTDR) |
|---|---|
Use Scenario: Amplifying fast-rising edge signals from passive probes or differential input stages before digitization. IC Role / Device Role / Timing Role: High-fidelity voltage buffer and gain stage with minimal group delay variation across 500MHz bandwidth. Use Value: Preserves signal integrity of sub-nanosecond edges via 550MHz unity-gain bandwidth and 1.3ns rise time. |
Use Scenario: Converting weak, nanosecond-scale photocurrent pulses from fiber backscatter into measurable voltage waveforms. IC Role / Device Role / Timing Role: Transimpedance amplifier with 100kΩ gain and 4MHz bandwidth in OTDR receiver chain. Use Value: Achieves 0.40pA/√Hz input-referred current noise using 6nV/√Hz voltage noise and low input bias current. |
| Active Probe Signal Conditioning | Medical Analyzer Photodetector Interface |
Use Scenario: Buffering and level-shifting high-frequency signals from compact active probe tips with minimal added noise. IC Role / Device Role / Timing Role: Low-capacitance, high-Z input buffer driving 50Ω transmission lines to scope input. Use Value: Maintains >100MHz small-signal bandwidth with <1dB peaking due to 550MHz GBW and optimized layout. |
Use Scenario: Amplifying low-level photocurrent from spectrophotometric or flow cytometry detectors. IC Role / Device Role / Timing Role: Precision transimpedance amplifier with stable DC offset and low drift for quantitative light measurement. Use Value: Delivers ±0.6mV max VOS and ±6μV/°C drift - enabling accurate baseline subtraction in multi-minute assays. |
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 |
|---|---|---|---|
| OPA814 | Higher GBW (250MHz), faster slew rate (750V/μs), lower voltage noise (5.3nV/√Hz), but higher input bias current (10pA) | Better for >250MHz small-signal amplification; less suitable for ultra-high-Z photodiode nodes | Select OPA814 when bandwidth >230MHz is required and input impedance >10¹² Ω is not critical |
| OPA659 | Higher GBW (350MHz), much higher slew rate (2550V/μs), higher voltage noise (8.9nV/√Hz), same 1-V/V minimum stable gain | Optimized for fast pulse amplification (e.g., LIDAR); trades noise performance for speed | Choose OPA659 for sub-ns pulse fidelity where integrated noise is secondary to rise time |
Compared with OPA656U, OPA814 offers tighter noise-bandwidth trade-off for mid-bandwidth applications, while OPA659 sacrifices voltage noise for extreme slew rate - making OPA656U the optimal balance for precision transimpedance and test equipment front-ends requiring both bandwidth and dc accuracy.
Availability
OPA656U is available at Aetrix Electronics and suitable for high-speed data acquisition, optical communication modules, and medical analyzer signal chains requiring stable component supply, traceable sourcing, and long-term lifecycle support.
Supply support for OPA656U 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 company specializing in analog and embedded processing solutions, with leadership in precision amplifiers, data converters, and high-speed interface ICs.
The OPA656U belongs to TI's OPA high-speed precision op-amp family, designed specifically for demanding transimpedance, active probe, and test-and-measurement front-end applications where unity-gain stability, low noise, and dc accuracy are simultaneously required.
FAQ
What is the maximum supply voltage for the OPA656U?
The OPA656U has an absolute maximum supply voltage rating of ±6.5V (13V total), but its recommended operating range is ±5V (8V–12V total). Operation beyond ±6V risks permanent damage per the Absolute Maximum Ratings table; sustained use at ±6.5V is not supported. The OPA656U achieves optimal distortion and bandwidth performance at ±5V, where slew rate reaches 400V/μs and harmonic distortion remains below –90dBc at 5MHz.
Does the OPA656U support single-supply operation?
Yes, the OPA656U supports single-supply operation with proper input common-mode and output swing constraints. When operated from +10V and ground, the input common-mode range extends from –3.7V to +2.75V (relative to ground), and output swing reaches ±3.5V into 100Ω. However, full-spec performance - including specified input offset voltage, PSRR, and distortion - is guaranteed only under dual-supply conditions (±5V) per the Electrical Characteristics tables.
How does the OPA656U compare to the OPA656UB variant?
The OPA656U is the standard-grade version, while OPA656UB is a high-grade variant with tighter DC specifications: ±0.1mV typical input offset voltage (vs. ±0.2mV for OPA656U), ±2μV/°C max drift (vs. ±6μV/°C), and improved CMRR (95dB min vs. 90dB). Both share identical AC performance, pinout, and package options. OPA656U remains suitable for most high-speed applications where ultimate DC precision is not required.
What is the recommended feedback capacitor for a 100kΩ transimpedance design with OPA656U?
For a 100kΩ transimpedance gain targeting 4MHz bandwidth with 20pF photodiode capacitance, the OPA656U datasheet recommends a 0.5pF feedback capacitor (CF) in parallel with PCB and amplifier input capacitance (~23.3pF total). This value sets the dominant pole to ~2.8MHz, yielding a measured closed-loop bandwidth of 4.2MHz in TINA SPICE simulation - matching the design requirement in Figure 8-3.
Is the OPA656U pin-compatible with other op-amps in the OPA656 family?
Yes, all OPA656 variants - including OPA656U, OPA656UB, and OPA656NB - share identical pinouts, package footprints (SOIC-8 and SOT-23-5), and AC specifications. Only DC parameters differ between grades. This allows drop-in replacement of OPA656U with OPA656UB in existing designs when tighter offset or drift specs are needed, without PCB or layout changes.
OPA656U Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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:
- 2 pA
- Voltage - Input Offset:
- 250 µV
- Current - Supply:
- 14mA
- Current - Output / Channel:
- 70 mA
- 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
OPA656U FAQ
1.How can I place an order for OPA656U through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA656U 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 OPA656U reliable?
The price and inventory of OPA656U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA656U is usually 5 days.
3.What payment methods are accepted for OPA656U?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA656U transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA656U?
OPA656U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA656U 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 OPA656U?
For technical support, including OPA656U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA656U requirements.
6.How does Aetrix verify that OPA656U is sourced from the original manufacturer or authorized distributors?
All OPA656U 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 OPA656U meets industry standards.
7.What is the process for return or replacement of OPA656U?
All OPA656U units undergo pre-shipment inspection (PSI). If there is an issue with OPA656U, 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 OPA656U part is unused and in its original packaging.
Return procedure for OPA656U:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
OPA656U Tags
-
LM358DT
STMicroelectronics
-
LM358DR
Texas Instruments
-
LM2904DR
Texas Instruments
-
LM358ADR
Texas Instruments
-
LM2904DGKR
Texas Instruments
-
LM324DR
Texas Instruments
-
MCP6006T-E/OT
Microchip Technology
-
MCP6006UT-E/OT
Microchip Technology
-
LM324PWR
Texas Instruments
-
LM2902PWR
Texas Instruments
-
LM2902DR
Texas Instruments
-
LM358P
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
