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Texas Instruments OPA657U/2K5
- Part No.:
- OPA657U/2K5
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA657U/2K5.pdf
- Description:
- IC VOLTAGE FEEDBACK 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,167
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Product details
Overview
OPA657U/2K5 from Texas Instruments is a 1.6-GHz gain-bandwidth, low-noise, FET-input voltage-feedback operational amplifier optimized for high-precision photodiode transimpedance and ADC driver applications. It delivers 275-MHz small-signal bandwidth at G = +10, 700 V/µs slew rate, 4.8 nV/√Hz input voltage noise, and operates from ±4 V to ±6 V supplies across –40°C to +85°C.
For engineers reviewing the OPA657U/2K5 datasheet, OPA657U/2K5 pinout, OPA657U/2K5 application, or OPA657U/2K5 equivalent, key selection criteria include its decompensated stability (minimum stable gain +7), JFET-input bias current of 2 pA (typ), 70 mA output drive, and SOIC-8 package thermal resistance of 125°C/W - critical for wideband optical front ends and test equipment signal chains.
Technical Context
The OPA657U/2K5 uses a decompensated voltage-feedback architecture with a high-speed complementary bipolar process and low-noise JFET input stage. Its 1.6-GHz gain-bandwidth product enables >10-MHz signal bandwidths up to G = +160 V/V while maintaining low distortion (–70 dBc 2nd-harmonic at 5 MHz).
It supports both split-supply (±4 V to ±6 V) and single-supply (8 V to 12 V) operation with rail-to-rail output swing capability (±3.3 V into 100 Ω). Input common-mode range extends to ±3.5 V, and fast overdrive recovery minimizes settling errors in pulsed optical detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain-Bandwidth Product | 1.6 GHz - enables ≥10-MHz closed-loop bandwidth at gains up to +160 V/V without compensation |
| Small-Signal Bandwidth (G = +10) | 275 MHz - supports high-fidelity amplification of fast photodiode currents or ADC input signals |
| Slew Rate | 700 V/µs - ensures minimal distortion on large-signal transients (e.g., OTDR pulse edges) |
| Input Voltage Noise | 4.8 nV/√Hz - provides exceptional sensitivity for low-light photodetection below 10-MHz bandwidth |
| Input Bias Current | 2 pA (typ) - preserves signal integrity with high-impedance sources like reverse-biased photodiodes |
| Output Current Drive | ±70 mA - drives 100-Ω loads directly, eliminating need for external buffers in many front-end designs |
| Operating Temperature Range | –40°C to +85°C - qualified for industrial and test equipment environments without derating |
Pinout & Package
OPA657U/2K5 is packaged in an 8-pin SOIC (D package) with body size 4.90 mm × 3.91 mm and thermal resistance RθJA = 125°C/W.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | No Connection | Internally unused; must be left floating or tied to ground per layout guidelines |
| 2 | Inverting Input (VIN–) | High-impedance node for feedback network connection; sensitive to parasitic capacitance |
| 3 | Noninverting Input (VIN+) | Low-bias-current JFET input; requires guard ring in transimpedance configurations |
| 4 | Negative Supply (–VS) | Accepts –4 V to –6 V in split-supply mode; connects to ground in single-supply biasing |
| 5 | Output (VOUT) | Capable of ±3.3 V swing into 100 Ω; requires series resistor for capacitive load stability |
| 6 | No Connection | Internally unused; no external connection required |
| 7 | Positive Supply (+VS) | Accepts +4 V to +6 V in split-supply mode; connects to VCC in single-supply operation |
| 8 | No Connection | Internally unused; must remain unconnected |
Key Features
| Feature | Design Value |
|---|---|
| Decompensated Stability | Stable at minimum gain of +7 - enables higher bandwidth than unity-gain-stable alternatives like OPA656 |
| JFET Input Stage | 2 pA input bias current and 4.8 nV/√Hz voltage noise - ideal for high-Z photodiode and sensor interfaces |
| High Output Drive | ±70 mA sourcing/sinking - directly drives 50 Ω or 100 Ω loads without external buffer stages |
| Fast Overdrive Recovery | <20 ns settling to 0.02% - maintains accuracy in pulsed optical time-domain reflectometry (OTDR) |
| ESD Protection | ±2000 V HBM - robust handling during PCB assembly and lab prototyping |
Applications
| Wideband Photodiode Amplifier | ADC Input Amplifier |
|---|---|
|
Use Scenario: Amplifying low-level current from high-speed photodiodes in fiber-optic receivers or laser rangefinders. IC Role / Device Role / Timing Role: Transimpedance amplifier converting photocurrent to voltage with minimal added noise and phase delay. Use Value: 4.8 nV/√Hz input voltage noise and 2 pA bias current yield 1.8 pA/√Hz total input-referred noise over 10 MHz - enabling sub-picoamp detection. |
Use Scenario: Driving high-resolution, high-speed analog-to-digital converters in oscilloscopes and spectrum analyzers. IC Role / Device Role / Timing Role: High-fidelity buffer and gain stage ensuring full-scale bandwidth and low harmonic distortion into ADC input capacitance. Use Value: 275-MHz bandwidth at G = +10 and –70 dBc 2nd-harmonic distortion preserve ENOB in 10-bit+ ADC systems sampling at 50+ MSPS. |
| Optical Time Domain Reflectometry (OTDR) | Test and Measurement Front End |
|
Use Scenario: Generating and receiving nanosecond-scale optical pulses to locate faults in fiber-optic cables. IC Role / Device Role / Timing Role: Fast pulse amplifier with sub-20 ns overdrive recovery for clean pulse shaping and echo capture. Use Value: 700 V/µs slew rate and 180-MHz large-signal bandwidth ensure faithful reproduction of <10 ns optical pulses without edge rounding. |
Use Scenario: Signal conditioning in automated test equipment (ATE) for semiconductor characterization. IC Role / Device Role / Timing Role: Precision gain block with low DC offset drift (±250 µV max) and high CMRR (83 dB) for accurate DC-coupled measurements. Use Value: ±250 µV input offset and ±12 µV/°C drift enable µV-level DC accuracy over temperature - critical for parametric testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-bandwidth, low-noise op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA656U | Unity-gain stable, 230-MHz GBW, 7 nV/√Hz noise, 290 V/µs slew rate | Better DC precision (±100 µV offset), lower noise floor above 100 kHz, but 4× lower bandwidth | Select when unity-gain stability or ultra-low DC error is required over bandwidth |
| OPA857ID | Transimpedance-optimized, 4.75-GHz GBW, integrated TIA architecture, 220 V/µs slew rate | Dedicated photodiode interface with internal feedback resistor; not a general-purpose op-amp | Select only for fixed-gain transimpedance applications where integration reduces layout complexity |
Compared with OPA657U/2K5, OPA656U trades bandwidth for stability and DC accuracy, while OPA857ID replaces general-purpose flexibility with application-specific transimpedance optimization - making OPA657U/2K5 the optimal choice for custom high-bandwidth, low-noise voltage-feedback designs requiring gain ≥ +7.
Availability
OPA657U/2K5 is available at Aetrix Electronics and suitable for wideband photodiode amplifiers, optical time-domain reflectometry (OTDR) systems, and high-speed ADC driver circuits requiring stable component supply, consistent parametric performance, and long-term industrial availability.
Supply support for OPA657U/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 company specializing in analog and embedded processing technologies, with leadership in high-performance op-amps, data converters, and signal chain solutions.
The OPA657U/2K5 belongs to TI's precision high-speed op-amp product line, designed specifically for demanding optical sensing, test instrumentation, and wideband signal acquisition applications where low noise, high bandwidth, and JFET-input integrity are essential.
FAQ
What is the minimum stable gain for OPA657U/2K5?
The OPA657U/2K5 is decompensated and specified as stable for noninverting gains of +7 V/V and higher. Operating below this gain risks peaking or oscillation; for unity-gain or G = +2 applications, TI recommends the OPA656U instead. The 7-dB peaking observed at G = +7 in typical characteristics confirms this boundary.
Does OPA657U/2K5 support single-supply operation?
Yes, OPA657U/2K5 supports single-supply operation from 8 V to 12 V. Input and output must be biased within the linear range (e.g., VCM = VCC/2), and the –VS pin connects to ground. Performance metrics including bandwidth and noise remain unchanged versus split-supply mode, as confirmed in Section 8.3.2 of the datasheet.
What is the input bias current specification for OPA657U/2K5 over temperature?
At TA = –40°C to +85°C, the input bias current for OPA657U/2K5 is ±5000 pA maximum. At 25°C, it is ±2 pA typical and ±20 pA maximum. This JFET-input characteristic remains stable across temperature, enabling reliable photodiode interfacing even in industrial environments.
Can OPA657U/2K5 drive a 50-Ω load directly?
Yes, OPA657U/2K5 can drive a 50-Ω load directly with ±70 mA output current. However, for optimal stability with capacitive loads >10 pF, TI recommends adding a 50-Ω series resistor at the output (Figure 17). Without this, frequency response may exhibit peaking or ringing due to output pole interaction.
What package type does OPA657U/2K5 use, and what is its thermal resistance?
OPA657U/2K5 uses the SOIC-8 (D package) with nominal body size 4.90 mm × 3.91 mm. Its junction-to-ambient thermal resistance (RθJA) is 125°C/W under standard JEDEC conditions, allowing continuous operation at up to 16.3 mA quiescent current without exceeding 125°C junction temperature at 25°C ambient.
OPA657U/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:
- 700V/µs
- Gain Bandwidth Product:
- 1.6 GHz
- -3db Bandwidth:
- 350 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
OPA657U/2K5 FAQ
1.How can I place an order for OPA657U/2K5 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA657U/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 OPA657U/2K5 reliable?
The price and inventory of OPA657U/2K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA657U/2K5 is usually 5 days.
3.What payment methods are accepted for OPA657U/2K5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA657U/2K5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA657U/2K5?
OPA657U/2K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA657U/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 OPA657U/2K5?
For technical support, including OPA657U/2K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA657U/2K5 requirements.
6.How does Aetrix verify that OPA657U/2K5 is sourced from the original manufacturer or authorized distributors?
All OPA657U/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 OPA657U/2K5 meets industry standards.
7.What is the process for return or replacement of OPA657U/2K5?
All OPA657U/2K5 units undergo pre-shipment inspection (PSI). If there is an issue with OPA657U/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 OPA657U/2K5 part is unused and in its original packaging.
Return procedure for OPA657U/2K5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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