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AD9631:  Ultralow Distortion, High Speed Op Amp, Stable at Gain of 1

Product Details

The AD9631/AD9632 are very high speed and wide bandwidth amplifiers. The AD9631 is unity gain stable. The AD9632 is stable at gains of 2 or greater. Using a voltage feedback architecture, the exceptional settling time, bandwidth, and low distortion of the AD9631/AD9632 meet the requirements of many applications that previously depended on current feedback amplifiers. Its classical op amp structure works much more predictably in many designs.

A proprietary design architecture has produced an amplifier that combines many of the best characteristics of both current feedback and voltage feedback amplifiers. The AD9631/AD9632 exhibit exceptionally fast and accurate pulse response (16 ns to 0.01%) as well as extremely wide small signal and large signal bandwidth and ultralow distortion. The AD9631 achieves −72 dBc at 20 MHz, 320 MHz small signal bandwidth, and 175 MHz large signal bandwidths.

These characteristics position the AD9631/AD9632 ideally for driving flash as well as high resolution ADCs. Additionally, the balanced high impedance inputs of the voltage feedback architecture allow maximum flexibility when designing active filters.

The AD9631/AD9632 are offered in the industrial (−40°C to +85°C) temperature range. They are available in PDIP and SOIC.


  • ADC input driver
  • Differential amplifiers IF/RF amplifiers
  • Pulse amplifiers
  • Professional video
  • DAC current to voltage
  • Baseband and video communications
  • Pin diode receivers
  • Active filters/integrators/log amps


  • Wide Bandwidth
    AD9631, G = +1
    Small signal
    320 MHz
    Large signal (4 V p-p)
    175 MHz
  • Ultralow Distortion (SFDR), Low Noise
    −113 dBc Typ @ 1 MHz
    −95 dBc Typ @ 5 MHz
    −72 dBc Typ @ 20 MHz
    46 dBm Third Order Intercept @ 25 MHz
    7.0 nV/√Hz Spectral Noise Density
  • High Speed
    Slew Rate 1300 V/µs
    Settling 16 ns to 0.01%, 2 V Step
    ±3 V to ±5 V Supply Operation
    17 mA Supply Current

Pin Configuration Diagram for AD9631


Title Content Type File Type
AD9631/AD9632: Ultralow Distortion, Wide Bandwidth Voltage Feedback Op Amps Data Sheet (Rev D, 02/2014) (pdf, 692 kB) Data Sheets PDF
AN-649: Using the Analog Devices Active Filter Design Tool  (pdf, 5301 kB) Application Notes PDF
AN-357: Operational Integrators  (pdf, 272 kB) Application Notes PDF
AN-581: Biasing and Decoupling Op Amps in Single Supply Applications  (pdf, 166 kB) Application Notes PDF
AN-356: User's Guide to Applying and Measuring Operational Amplifier Specifications  (pdf, 538 kB) Application Notes PDF
AN-402: Replacing Output Clamping Op Amps with Input Clamping Amps  (pdf, 55 kB)
So far most clamping amplifiers have relied upon an output clamping architecture and are called output clamp amps (OCAs). A new architecture called an input clamp amp (ICA) offers superior clamping accuracy and lower distortion.
Application Notes PDF
AN-417: Fast Rail-to-Rail Operational Amplifiers Ease Design Constraints in Low Voltage High Speed Systems  (pdf, 228 kB)
Movement towards lower power supply voltages is driven by the demand that systems consume less and less power coupled with the desire to reduce the number of power supply voltages in the system. The following applications are discussed: Single-Ended and Differential Input ADC Input Circuits, Video Line Driver, Active Filter, HDSL Transceiver, and Transformer Drive Circuits.
Application Notes PDF
MT-060: Choosing Between Voltage Feedback and Current Feedback Op Amps  (pdf, 62 kB) Tutorials PDF
MT-059: Compensating for the Effects of Input Capacitance on VFB and CFB Op Amps Used in Current-to-Voltage Converters  (pdf, 69 kB) Tutorials PDF
MT-058: Effects of Feedback Capacitance on VFB and CFB Op Amps  (pdf, 66 kB) Tutorials PDF
MT-056: High Speed Voltage Feedback Op Amps  (pdf, 109 kB) Tutorials PDF
MT-053: Op Amp Distortion: HD, THD, THD + N, IMD, SFDR, MTPR  (pdf, 104 kB) Tutorials PDF
MT-052: Op Amp Noise Figure: Don't Be Misled  (pdf, 60 kB) Tutorials PDF
MT-050: Op Amp Total Output Noise Calculations for Second-Order System  (pdf, 38 kB) Tutorials PDF
MT-049: Op Amp Total Output Noise Calculations for Single-Pole System  (pdf, 40 kB) Tutorials PDF
MT-048: Op Amp Noise Relationships: 1/f Noise, RMS Noise, and Equivalent Noise Bandwidth  (pdf, 81 kB) Tutorials PDF
MT-047: Op Amp Noise  (pdf, 72 kB) Tutorials PDF
MT-033: Voltage Feedback Op Amp Gain and Bandwidth  (pdf, 251 kB) Tutorials PDF
MT-032: Ideal Voltage Feedback (VFB) Op Amp  (pdf, 65 kB) Tutorials PDF
A Stress-Free Method for Choosing High-Speed Op Amps
A decision-tree approach to making the critical decision about high-speed op amp selection, including a look at some helpful tools.
Webcasts WEBCAST
UG-101: Evaluation Board User Guide  (pdf, 189 kB) User Guides PDF
Ask the Applications Engineer-18
Settling Time

(Analog Dialogue, Vol. 29, No. 2, 1995)
Analog Dialogue HTML
Choosing High-Speed Signal Processing Components for Ultrasound Systems
(Analog Dialogue, Vol. 29, No. 2, 1995)
Analog Dialogue HTML
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
dBm/dBu/dBv Calculator
This calculator converts between standard units of power measurement and signal strength.
Utilities and Conversions HTML
Power Dissipation vs Die Temp
This tool estimates die temperature and power dissipation based on the supply voltages, ambient temperature, load characteristics, and package thermal data.
Utilities and Conversions HTML
This tool will help with the selection, evaluation and troubleshooting of voltage feedback Op-Amps. It uses typical data to model the behavior of a selected amplifier. It allows a user to select an amplifier, configure a circuit, apply a signal and evaluate the performance. It is useful for checking an amplifier's spec's such as Bandwidth, Slew Rate, Input/Output Range, Gain Error, Load Current, Stability Issues and DC Errors in a given circuit.
ADIsim Design/Simulation Tools HTML
OpAmp Stability
An applet for demonstrating stability effects in opamp buffers.
Design Calculators HTML
AD9631AN SPICE Macro-Model SPICE Models HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

SampleSample & Buy

Price, packaging, availability

AD9631 Model Options
Model Package Pins Temp.
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
AD9631ACHIPS Status: Production CHIPS OR DIE 0 Comm. Tray, 210 - $5.33 Y  Material Info Notify Me Contact ADI
AD9631ANZ Status: Production 8 ld PDIP 8 Ind Tube, 50 $5.61 $4.77 Y  Material Info PCN Purchase
AD9631AR Status: Last Time Buy 8 ld SOIC 8 Ind Tube, 98 $6.15 $5.23 N  Material Info PDN Purchase
AD9631AR-REEL Status: Last Time Buy 8 ld SOIC 8 Ind Reel, 2500 - $5.23 N  Material Info PDN Purchase
AD9631AR-REEL7 Status: Production 8 ld SOIC 8 Ind Reel, 750 - $5.23 N  Material Info Notify Me Purchase
AD9631ARZ Status: Production 8 ld SOIC 8 Ind Tube, 98 $5.61 $4.77 Y  Material Info Notify Me Purchase
AD9631ARZ-REEL Status: Production 8 ld SOIC 8 Ind Reel, 2500 - $4.77 Y  Material Info Notify Me Purchase
AD9631ARZ-REEL7 Status: Production 8 ld SOIC 8 Ind Reel, 750 - $4.77 Y  Material Info Notify Me Purchase
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

AD9631 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
AD9631AR-EBZ Status: Production 8-Lead SOIC Bare Evaluation Board $18.25 Yes -
AD9631ARZ Status: Production 8-Lead SOIC $7.86 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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