The ADA4939 is a low noise, ultralow distortion, high speed differential amplifier. It is an ideal choice for driving high performance ADCs with resolutions up to 16 bits from dc to 100 MHz. The output common-mode voltage is user adjustable by means of an internal common-mode feedback loop, allowing the ADA4939 output to match the input of the ADC. The internal feedback loop also provides exceptional output balance as well as suppression of even-order harmonic distortion products.
With the ADA4939, differential gain configurations are easily realized with a simple external feedback network of four resistors that determine the closed-loop gain of the amplifier.
The ADA4939 is fabricated using Analog Devices, Inc., proprietary silicon-germanium (SiGe), complementary bipolar process, enabling it to achieve very low levels of distortion with an input voltage noise of only 2.3 nV/√Hz. The low dc offset and excellent dynamic performance of the ADA4939 make it well suited for a wide variety of data acquisition and signal processing applications.
The ADA4939 is available in a Pb-free, 3 mm × 3 mm 16-lead LFCSP (ADA4939-1, single) or a Pb-free, 4 mm × 4 mm 24-lead LFCSP (ADA4939-2, dual). The pinout has been optimized to facilitate PCB layout and minimize distortion. The ADA4939-1 and the ADA4939-2 are specified to operate over the −40°C to +105°C temperature range; both operate on supplies between 3.3 V and 5 V.
Data Sheet, Rev. 0, 5/08
|Title||Content Type||File Type|
|ADA4939-1/ADA4939-2: Ultralow Distortion Differential ADC Driver Data Sheet (Rev 0, 05/2008) (pdf, 622 kB)||Data Sheets|
|AN-1026: High Speed Differential ADC Driver Design Considerations (pdf, 355 kB)||Application Notes|
|AN-0990: Terminating a Differential Amplifier in Single-Ended Input Applications (pdf, 181 kB)||Application Notes|
|AN-0992: Active Filter Evaluation Board for Differential Amplifiers (pdf, 85 kB)||Application Notes|
|AN-282: Fundamentals of Sampled Data Systems (pdf, 2131 kB)||Application Notes|
|AN-649: Using the Analog Devices Active Filter Design Tool (pdf, 5301 kB)||Application Notes|
AN-584: Using the AD813X Differential Amplifier
(pdf, 174 kB)
The AD813x differs from conventional op amps by the external presence of an additional input and output. The additional input, VOGM, controls the output common mode voltage.
AN-589: Ways to Optimize the Performance of a Difference Amplifier
(pdf, 115 kB)
This Application Note presents several ways to build and optimize the performance of a discrete difference amplifier. It also recommends amplifiers that will make the overall solution cost/performance competitive with monolithic instrument amplifiers.
|MT-218: Multiple Feedback Band-Pass Design Example (pdf, 0)||Tutorials|
|MT-076: Differential Driver Analysis (pdf, 95 kB)||Tutorials|
|MT-075: Differential Drivers for High Speed ADCs Overview (pdf, 183 kB)||Tutorials|
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.
|UG-018: Evaluation Board for Dual High Speed Differential Amplifiers (pdf, 314 kB)||User Guides|
"Rules of the Road" for High-Speed Differential ADC Drivers
(Analog Dialogue, Vol. 43, No. 5, 2009)
RF Source Booklet
(PDF, 4353 kB)
RF IC Product Overview - Version P (02/2014)
|RAQs index||Rarely Asked Questions||HTML|
|Glossary of EE Terms||Glossary||HTML|
|Title||Content Type||File Type|
ADI's new ADI DiffAmpCalc is a free, downloadable calculator for designing differential amplifier circuits. The tool is easy to use and features an interactive user interface to quickly get you up and running.
|ADIsim Design/Simulation Tools||HTML|
|ADA4939 SPICE Macro Model (cir)||SPICE Models||CIR|
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.