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Texas Instruments OPA657NB/3K
- Part No.:
- OPA657NB/3K
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SC-74A, SOT-753
- Datasheet:
-
OPA657NB/3K.pdf
- Description:
- IC OPAMP VFB 1 CIRCUIT SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,772
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Product details
Overview
OPA657NB/3K 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, and 4.8 nV/√Hz input voltage noise in a 5-pin SOT-23 package, enabling wideband signal amplification with minimal distortion in optical front ends.
For engineers reviewing the OPA657NB/3K datasheet, OPA657NB/3K pinout, OPA657NB/3K application, or OPA657NB/3K equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation insights, and two confirmed alternative parts with documented functional and application differences.
Technical Context
The OPA657NB/3K 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 stable operation at minimum gain of +7, supporting >10-MHz signal bandwidths up to 160 V/V (44 dB) gain.
It features split-supply operation (±4 V to ±6 V) with symmetric output swing around ground, and supports single-supply use (8–12 V) when input/output biasing remains within linear range. Input bias current is 2 pA (typ), input capacitance is 0.7 pF (differential) / 4.5 pF (common-mode), and it includes ESD protection diodes rated for ±2000-V HBM.
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 stability compromise. |
| Small-Signal Bandwidth (G = +10) | 275 MHz - Supports high-fidelity amplification of fast pulses and RF-modulated optical signals. |
| Slew Rate | 700 V/µs - Ensures <20 ns settling to 0.02% for 2-V step inputs, critical for time-domain reflectometry (OTDR). |
| Input Voltage Noise | 4.8 nV/√Hz - Delivers exceptional sensitivity for low-light photodiode detection with minimal added noise floor. |
| Input Bias Current | 2 pA (typ) - Allows direct interfacing with high-impedance photodiodes (>100 kΩ) without significant DC error. |
| Output Current Drive | ±70 mA - Drives 100-Ω loads with full ±3.3-V swing, sufficient for ADC input buffering and 50-Ω test equipment interfaces. |
| Operating Temperature Range | –40°C to +85°C - Qualified for industrial and instrumentation environments with guaranteed performance across full range. |
Pinout & Package
OPA657NB/3K is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for high-frequency layout with low parasitic inductance and thermal resistance (RθJA = 150°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Amplifier Output | Delivers full-swing output (±3.3 V into 100 Ω); requires local 0.1-µF bypass capacitor to minimize supply impedance. |
| 2 (–VS) | Negative Power Supply | Accepts –4 V to –6 V in split-supply mode; must be decoupled with 6.8-µF + 0.1-µF capacitors for stability. |
| 3 (IN+) | Noninverting Input | High-impedance JFET node (1012 Ω || 4.5 pF); sensitive to layout-induced capacitance-keep trace short and guard-ring isolated. |
| 4 (IN–) | Inverting Input | Differential input node (1012 Ω || 0.7 pF); forms feedback network with RF/ RG; dominant pole location depends on RF || RG parallel value. |
| 5 (+VS) | Positive Power Supply | Accepts +4 V to +6 V in split-supply mode; shares same decoupling requirements as –VS for PSRR optimization. |
Key Features
| Feature | Design Value |
|---|---|
| Low input voltage noise | 4.8 nV/√Hz enables sub-picoamp photocurrent detection in 10-MHz bandwidth photodiode amplifiers. |
| High slew rate | 700 V/µs ensures faithful reproduction of fast optical pulses without slew-induced distortion in OTDR systems. |
| Fast overdrive recovery | Sub-20 ns recovery from saturation allows accurate capture of closely spaced optical reflections in time-domain measurements. |
| High-output current | ±70 mA drive capability supports direct connection to 50-Ω lab equipment and 100-Ω ADC input networks without external buffers. |
| ESD-protected inputs | ±2000-V HBM rating permits robust handling during PCB assembly and system integration without additional protection circuitry. |
Applications
| Wideband Photodiode Amplifier | Optical Time Domain Reflectometry (OTDR) |
|---|---|
Use Scenario: Amplifying weak, fast-rising photocurrents from fiber-optic photodiodes in laser-based sensing systems. IC Role / Device Role / Timing Role: Transimpedance amplifier converting nanoamp-level photocurrents into clean voltage signals 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, maximizing dynamic range for low-light detection. | Use Scenario: Generating and capturing nanosecond-scale optical pulse reflections to locate faults in fiber-optic cables. IC Role / Device Role / Timing Role: High-speed pulse amplifier and driver in both transmit and receive paths, requiring precise edge fidelity and fast recovery. Use Value: 700 V/µs slew rate and <20 ns 0.02% settling enable accurate timing resolution of reflections separated by <10 ns, directly improving fault-location accuracy. |
| ADC Input Amplifier | Test and Measurement Front End |
Use Scenario: Buffering and gain-setting analog signals before digitization in high-speed data acquisition systems. IC Role / Device Role / Timing Role: Driver amplifier matching ADC input impedance while preserving signal integrity up to Nyquist frequency. Use Value: 275-MHz bandwidth at G = +10 and ±3.3-V output swing into 100 Ω ensure full-scale signal delivery to 100-MSPS+ ADCs with <0.1 dB flatness to 30 MHz. | Use Scenario: Signal conditioning in oscilloscope front ends, spectrum analyzers, and automated test equipment. IC Role / Device Role / Timing Role: Wideband gain block providing calibrated amplification, low-noise pre-amplification, and impedance transformation. Use Value: 1.6-GHz GBP and 700 V/µs slew rate support multi-hundred-MHz signal paths with minimal group delay variation, essential for vector signal analysis accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-bandwidth, low-noise amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA656IDBVR | Unity-gain stable; lower GBP (230 MHz); higher input voltage noise (7 nV/√Hz); 290 V/µs slew rate. | Preferred for G = +1 applications where stability without external compensation is required; unsuitable for >100-MHz transimpedance designs. | Select OPA656IDBVR only when unity-gain operation or lower power (11 mA IQ) is prioritized over bandwidth and noise performance. |
| OPA659IDBVR | Unity-gain stable; 350-MHz GBP; higher input voltage noise (8.9 nV/√Hz); 2550 V/µs slew rate; bipolar input. | Better suited for high-slew, moderate-noise applications with resistive sources; not recommended for high-impedance photodiode interfaces due to 500 pA bias current. | Choose OPA659IDBVR when driving low-Z loads with large signal swings where speed outweighs input current and noise constraints. |
Compared with OPA656IDBVR and OPA659IDBVR, the OPA657NB/3K uniquely balances ultra-high GBP (1.6 GHz), ultra-low input voltage noise (4.8 nV/√Hz), and femtoamp-level input bias current (2 pA), making it the only viable option for precision wideband transimpedance amplification above 50 MHz with photodiodes.
Availability
OPA657NB/3K 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 OPA657NB/3K 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 interface solutions.
The OPA657NB/3K belongs to TI's precision high-speed amplifier product line, designed specifically for optical sensing, test equipment, and high-fidelity signal chain applications demanding low noise, high bandwidth, and excellent DC accuracy.
FAQ
What is the minimum stable gain for OPA657NB/3K?
The OPA657NB/3K is decompensated and requires a minimum noninverting gain of +7 for stable operation. Attempting unity-gain or G = +2 configurations will result in peaking and potential oscillation. For lower gains, TI recommends the unity-gain stable OPA656 or OPA659. The OPA657NB/3K datasheet specifies 7-dB peaking at G = +7, confirming its intentional decompensation for bandwidth optimization.
Does OPA657NB/3K support single-supply operation?
Yes, OPA657NB/3K supports single-supply operation from 8 V to 12 V, provided input and output common-mode voltages remain within the linear operating range (typically 1.8 V above –VS and 3.5 V below +VS). In single-supply mode, the –VS pin connects to ground, and input biasing must shift signal references accordingly. Performance metrics-including bandwidth, slew rate, and noise-remain identical to split-supply operation when properly biased.
What is the input capacitance of OPA657NB/3K?
The OPA657NB/3K has a differential input capacitance of 0.7 pF and a common-mode input capacitance of 4.5 pF, as measured at 25°C with ±5-V supplies. These values directly impact stability in transimpedance configurations: the 4.5-pF common-mode capacitance interacts with photodiode junction capacitance and feedback resistor to form a pole that must be compensated via feedback capacitor or series resistor. Layout parasitics can add 0.2–0.5 pF, so guard rings and short traces are essential.
Can OPA657NB/3K drive a 50-Ω load directly?
OPA657NB/3K is not specified to drive a 50-Ω load continuously at full output swing. Its typical output swing is ±3.3 V into 100 Ω; driving 50 Ω reduces swing to approximately ±2.8 V and increases quiescent current. For sustained 50-Ω operation, TI recommends using a series 50-Ω resistor at the output (as shown in Figure 29) to isolate the amplifier from the matched load, preserving stability and thermal performance while maintaining signal integrity for lab equipment interfacing.
What is the maximum junction temperature for OPA657NB/3K?
The absolute maximum junction temperature for OPA657NB/3K is 175°C, per the Absolute Maximum Ratings table. However, the recommended operating ambient temperature range is –40°C to +85°C. With RθJA = 150°C/W in the SOT-23 package, dissipating 16 mA × 10 V = 160 mW raises junction temperature by 24°C above ambient-well within safe limits. Thermal derating begins above 125°C junction, and continuous operation above 150°C risks accelerated parameter drift and reliability degradation.
OPA657NB/3K Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 1 pA
- Voltage - Input Offset:
- 100 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:
- SOT-23-5
OPA657NB/3K FAQ
1.How can I place an order for OPA657NB/3K through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA657NB/3K 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 OPA657NB/3K reliable?
The price and inventory of OPA657NB/3K are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA657NB/3K is usually 5 days.
3.What payment methods are accepted for OPA657NB/3K?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA657NB/3K transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA657NB/3K?
OPA657NB/3K orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA657NB/3K 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 OPA657NB/3K?
For technical support, including OPA657NB/3K datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA657NB/3K requirements.
6.How does Aetrix verify that OPA657NB/3K is sourced from the original manufacturer or authorized distributors?
All OPA657NB/3K 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 OPA657NB/3K meets industry standards.
7.What is the process for return or replacement of OPA657NB/3K?
All OPA657NB/3K units undergo pre-shipment inspection (PSI). If there is an issue with OPA657NB/3K, 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 OPA657NB/3K part is unused and in its original packaging.
Return procedure for OPA657NB/3K:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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