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Texas Instruments OPA688P
- Part No.:
- OPA688P
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
OPA688P.pdf
- Description:
- IC OPAMP VFB 290MHZ SGL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:500
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Product details
Overview
OPA688P from Texas Instruments is a unity-gain stable, wideband voltage-limiting amplifier with bipolar output voltage limiting architecture. It delivers ±15mV limiting voltage accuracy, 530MHz –3dB bandwidth at G = +1, 1000V/µs slew rate, and 2.4ns recovery from overdrive - enabling precise signal conditioning in high-speed ADC input buffers and video sync stripping applications.
For engineers reviewing the OPA688P datasheet, OPA688P pinout, OPA688P application, or OPA688P equivalent, this page provides verified technical context, SO-8 package mapping, limiting-mode AC/DC performance, real-world application cards for fast limiting and analog signal processing, and two validated alternative parts with functional and application-level distinctions.
Technical Context
The OPA688P implements output-stage voltage limiting via dedicated limiter pins (5 and 8), decoupling limiting accuracy from gain configuration - ensuring ±15mV offset error across all closed-loop gains. Its voltage-feedback architecture supports unity-gain stability while maintaining 530MHz small-signal bandwidth and 145MHz large-signal bandwidth (4Vp-p, ±2.5V limits).
Limiter operation is independent of op amp core saturation: linear operation holds within 30mV of limit thresholds, and recovery from full overdrive occurs in ≤2.4ns (max). Limiter feedthrough is –60dB at 5MHz, and limiter small-signal bandwidth reaches 450MHz in limiting mode - preserving integrity of clipped edges in HF mixer and IF limiting amplifier use cases.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| –3dB Bandwidth (G = +1) | 530MHz - enables direct drive of 50Ω transmission lines without external equalization in video or RF signal paths. |
| Slew Rate | 1000V/µs - supports clean 4Vp-p step response with <3ns rise/fall time, critical for fast-limiting ADC front-ends. |
| Limiter Voltage Accuracy | ±15mV - ensures precise clamping to set thresholds (e.g., ±2.0V) without calibration, reducing system-level offset drift. |
| Recovery Time from Limiting | 2.4ns (max) - guarantees minimal dead time between clipped pulses in CCD pixel clock stripping or AM signal generation. |
| Supply Range | ±5V or +5V single supply - allows deployment in both dual-rail instrumentation and cost-sensitive single-supply embedded systems. |
| Input Noise Density | 6.3nV/√Hz (≥1MHz) - maintains SNR >60dB in 5MHz spurious-free dynamic range measurements with 2Vp-p output. |
| Output Current Drive | ±85mA (min) - drives 500Ω loads directly while sustaining linearity guardband of 30mV near limit voltages. |
Pinout & Package
OPA688P is housed in an industry-standard SO-8 surface-mount package (JEDEC MS-012AC, 8-pin, 1.27mm pitch), with thermal resistance θJA = 125°C/W. Pin functions are validated per TI SBOS082A datasheet Figure 1 and Pin Configuration diagram.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (NC) | No Connect | Internally unused; must be left floating or tied to ground per layout best practices - no routing required. |
| 2 (Inverting Input) | Inverting Input Node | Differential input terminal; requires matched 50Ω source termination for optimal 530MHz bandwidth in G = +1 configurations. |
| 3 (Non-Inverting Input) | Non-Inverting Input Node | High-impedance input (1MΩ || 1pF); used for DC-coupled non-inverting amplifiers or precision half-wave rectifier topologies. |
| 4 (–VS) | Negative Supply Rail | Accepts –5V (dual supply) or ground (single supply); bypassed with 0.1µF ceramic capacitor placed <0.2" from pin. |
| 5 (VH) | Positive Limiter Control | Sets upper output limit voltage; bias current magnitude 54µA (min) - requires low-impedance source (e.g., resistor divider from VCM). |
| 6 (Output) | Amplified/Limited Output | Buffered output capable of sourcing/sinking ±85mA; includes internal isolation resistor for stability with capacitive loads. |
| 7 (+VS) | Positive Supply Rail | Accepts +5V (dual or single supply); bypassed identically to Pin 4; shared with limiter bias networks in single-supply designs. |
| 8 (VL) | Negative Limiter Control | Sets lower output limit voltage; bias current polarity opposite VH; minimum separation 200mV enforced for stable limiting action. |
Key Features
| Feature | Design Value |
|---|---|
| Bipolar output voltage limiting | Independent control of upper (VH) and lower (VL) limits via dedicated pins - eliminates need for external clamp diodes or feedback-based limiters. |
| ±15mV limiter offset accuracy | Guaranteed across temperature (–40°C to +85°C) - enables sub-50mV guardband design for 10-bit+ ADC input protection without trimming. |
| 2.4ns recovery from overdrive | Measured under 2V step from ±2V to 0V - preserves pulse fidelity in CCD pixel clock stripping and fast comparator applications. |
| 450MHz limiter small-signal bandwidth | Validated at VIN = ±2V, VO < 0.02Vp-p - ensures sharp transition and minimal phase distortion during clipping of HF mixer outputs. |
| Unity-gain stable voltage-feedback core | Supports G = +1 to +5 configurations without compensation - simplifies design of ADC drivers, Schmitt triggers, and DC restorers. |
Applications
| Fast Limiting ADC Input Buffers | CCD Pixel Clock Stripping |
|---|---|
Use Scenario: Driving 10-bit, 40MSPS ADC (e.g., ADS822) with ±1.5V input range in single +5V system, where input transients exceed rail limits. IC Role / Device Role / Timing Role: Precision limiting buffer that clamps input to ±1.4V with ±15mV accuracy and recovers in 2.4ns - preventing ADC saturation and pipeline errors. Use Value: Eliminates need for external TVS or series resistors; maintains SFDR >62dB at 5MHz while protecting against ±3V overvoltage events. |
Use Scenario: Extracting pixel clock timing from high-speed CCD analog video output with 20MHz fundamental frequency and fast edge transitions. IC Role / Device Role / Timing Role: High-bandwidth limiter that strips sync pulses by hard-clipping composite video to ±2.0V levels with <3ns edge preservation. Use Value: Enables reliable clock recovery with <0.02° differential phase error (NTSC/PAL) and 0.02% differential gain - meeting broadcast-grade video specs. |
| Video Sync Stripping | IF Limiting Amplifiers |
Use Scenario: Isolating horizontal/vertical sync pulses from baseband NTSC video signals in professional video equipment. IC Role / Device Role / Timing Role: Fast-recovery limiting amplifier operating at G = +2, using VH/VL pins to define ±1.2V thresholds referenced to 2.5V common-mode. Use Value: Delivers 240MHz large-signal bandwidth and 250mV overshoot on 2x overdrive steps - ensuring clean, jitter-free sync edge detection. |
Use Scenario: Intermediate-frequency stage in 70MHz IF receiver chain requiring amplitude-stable limiting before demodulation. IC Role / Device Role / Timing Role: Wideband IF limiter with 145MHz large-signal BW and –60dB limiter feedthrough - suppressing AM noise while passing FM/PM content. Use Value: Provides 66dB SFDR at 5MHz and <10ns settling to 0.05%, enabling high-fidelity IF signal conditioning without AGC complexity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage-limiting amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA689ID | Higher gain version (G ≥ +5 optimized); 290MHz GBW vs OPA688P's 275MHz; same SO-8 package and limiter architecture. | Preferred for transimpedance amplifiers and high-gain IF stages where gain >+5 is required; not recommended for unity-gain ADC buffers. | Select OPA689ID when closed-loop gain exceeds +5 and limiter accuracy at high gain is critical - retains identical limiter pin behavior and 2.4ns recovery. |
| LMH6723MA/NOPB | No integrated voltage limiting; 650MHz –3dB BW at G = +2 but requires external clamping; higher input bias current (±12µA vs ±6µA max). | Suitable for general-purpose high-speed buffering where limiting is implemented externally (e.g., with fast Schottky diodes); lacks guaranteed limiter accuracy. | Choose LMH6723MA/NOPB only if board space allows discrete clamping and ±15mV limiter tolerance is not required - offers wider bandwidth but no built-in limiting. |
Compared with OPA688P, OPA689ID extends usable gain range while preserving limiting fidelity, whereas LMH6723MA/NOPB trades integrated limiting for raw bandwidth - making OPA688P the sole choice when guaranteed ±15mV clamping and sub-3ns recovery are mandatory.
Availability
OPA688P is available at Aetrix Electronics and suitable for fast limiting ADC input buffers, CCD pixel clock stripping, video sync stripping, and IF limiting amplifier applications requiring stable component supply across industrial and test equipment production cycles.
Supply support for OPA688P 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-speed op amps and precision signal chain solutions.
The OPA688P belongs to TI's OPA68x family of voltage-limiting amplifiers, designed specifically for applications demanding deterministic output clamping, ultrafast overdrive recovery, and wideband linearity - such as high-speed data acquisition and broadcast video signal processing.
FAQ
What is the maximum supply voltage rating for the OPA688P?
The OPA688P has an absolute maximum supply voltage rating of ±6.5V DC. Operation beyond ±6V risks junction breakdown and permanent damage. For reliable long-term performance, TI specifies ±5V nominal operation - with guaranteed performance up to ±6V under transient conditions. The OPA688P datasheet confirms 125°C/W junction-to-ambient thermal resistance in SO-8 package, making thermal derating essential above ±5V.
Does the OPA688P require external compensation for unity-gain stability?
No, the OPA688P is internally compensated for unity-gain stability. Its voltage-feedback architecture achieves stable operation at G = +1 without external components, delivering 530MHz –3dB bandwidth and <11dB gain peaking. TI recommends a minimum 24.9Ω series feedback resistor (RF) in unity-gain buffer configurations to isolate output from PCB inductance - a layout requirement, not a compensation necessity. The OPA688P datasheet explicitly states "unity gain stable" in the FEATURES section.
How does limiter feedthrough affect signal integrity in the OPA688P?
Limiter feedthrough in the OPA688P is –60dB at 5MHz, meaning any AC signal injected onto VH or VL pins appears at the output attenuated by 60dB. This prevents coupling of power-supply noise or reference ripple into the signal path. In practice, this allows direct connection of limiter pins to resistor dividers from clean references - critical in ADC driver applications where 0.02° differential phase error must be maintained. Measured feedthrough remains ≤–55dB up to 50MHz.
Can the OPA688P operate from a single +5V supply with rail-to-rail input/output?
The OPA688P operates from a single +5V supply but is not rail-to-rail. Its common-mode input range is specified as VCM ±0.8V at 25°C (min ±0.6V over temperature), and output swing is VCM ±1.6V into 500Ω. With VCM = 2.5V, this yields ~0.9V to 4.1V output range - sufficient for many single-supply ADC drivers. Input must remain within 1.7V to 3.3V. The OPA688P datasheet Figure 2 shows a working single-supply non-inverting amplifier with VH = 3.7V and VL = 1.3V.
What is the guaranteed limiter voltage separation for the OPA688P?
The OPA688P guarantees a minimum limiter voltage separation (VH – VL) of 200mV across temperature (–40°C to +85°C), as confirmed in the OUTPUT VOLTAGE LIMITERS table of the SBOS082A datasheet. This ensures stable limiting action even with resistor-divider drift or temperature-induced bias current variation. Attempting separation below 200mV may cause erratic limiting or oscillation - TI recommends ≥300mV design margin for production robustness.
OPA688P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SpeedPlus™
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- Voltage Feedback
- Number of Circuits:
- 1
- Output Type:
- Single-Ended
- Slew Rate:
- 1000V/µs
- Gain Bandwidth Product:
- 290 MHz
- -3db Bandwidth:
- 530 MHz
- Current - Input Bias:
- 6 µA
- Voltage - Input Offset:
- 2 mV
- Current - Supply:
- 15.8mA
- Current - Output / Channel:
- 105 mA
- Voltage - Supply Span (Min):
- 5 V
- Voltage - Supply Span (Max):
- 12 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
OPA688P FAQ
1.How can I place an order for OPA688P through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA688P 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 OPA688P reliable?
The price and inventory of OPA688P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA688P is usually 5 days.
3.What payment methods are accepted for OPA688P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA688P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA688P?
OPA688P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA688P 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 OPA688P?
For technical support, including OPA688P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA688P requirements.
6.How does Aetrix verify that OPA688P is sourced from the original manufacturer or authorized distributors?
All OPA688P 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 OPA688P meets industry standards.
7.What is the process for return or replacement of OPA688P?
All OPA688P units undergo pre-shipment inspection (PSI). If there is an issue with OPA688P, 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 OPA688P part is unused and in its original packaging.
Return procedure for OPA688P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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