The AD8138 is a major advancement over op amps for differential signal processing. The AD8138 can be used as a single-ended-to-differential amplifier or as a differential-to-differential amplifier. The AD8138 is as easy to use as an op amp, and greatly simplifies differential signal amplification and driving. Manufactured on ADI's proprietary XFCB bipolar process, the AD8138 has a -3 dB bandwidth of 320 MHz and delivers a differential signal with the lowest harmonic distortion available in a differential amplifier. The AD8138 has a unique internal feedback feature that provides balanced output gain and phase matching, suppressing even order harmonics. The internal feedback circuit also minimizes any gain error that would be associated with the mismatches in the external gain setting resistors.
The AD8138's differential output helps balance the input to differential ADCs, maximizing the performance of the ADC. The AD8138 eliminates the need for a transformer with high performance ADCs, preserving the low frequency and dc information. The common-mode level of the differential output is adjustable by a voltage on the VOCM pin, easily level-shifting the input signals for driving single supply ADCs. Fast overload recovery preserves sampling accuracy.
The AD8138 distortion performance makes it an ideal ADC driver for communication systems, with distortion performance good enough to drive state-of-the-art 10-bit to 16-bit converters at high frequencies. The AD8138's high bandwidth and IP3 also make it appropriate for use as a gain block in IF and baseband signal chains. The AD8138 offset and dynamic performance make it well suited for a wide variety of signal processing and data acquisition applications.
The AD8138 is available in both SOIC and MSOP packages for operation over -40°C to +85°C temperatures.
The AD8138-EP supports defense and aerospace applications (AQEC)
Analog Devices introduces the next generation of Differential Amplifiers, these new amplifiers offer higher performance and lower power consumption than previous devices. Also new in this category, is each of these devices are offered as dual amplifiers, which simplifies designs and reduces board area.
|Title||Content Type||File Type|
|AD8138: Low Distortion Differential ADC Driver Data Sheet (Rev F, 01/2006) (pdf, 489 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-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.
|CN-0061: DC-Coupled, Single-Ended-to-Differential Conversion Using the AD8138 Low Distortion Differential ADC Driver and AD7357 Dual, 4.2 MSPS, 14-Bit SAR ADC (pdf, 96 kB)||Circuit Note|
|CN-0041: DC-Coupled, Single-Ended-to-Differential Conversion Using the AD8138 Low Distortion Differential ADC Driver and the AD7356 5 MSPS, 12-Bit SAR ADC (pdf, 98 kB)||Circuit Note|
|CN-0040: DC-Coupled, Single-Ended-to-Differential Conversion Using the AD8138 Low Distortion Differential ADC Driver and the AD7352 Dual, 3 MSPS, 12-Bit SAR ADC (pdf, 108 kB)||Circuit Note|
|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-474: Evaluation Board for Differential Amplifiers Offered in 8-Lead SOIC Packages (PDF, 263 kB)||User Guides|
|UG-130: Differential Amplifier Evaluation Board for 8-lead SOIC and MSOP Packages (pdf, 493 kB)||User Guides|
Ask The Application Engineer 36, Wideband A/D Converter Front-End Design Considerations II: Amplifier-or Transformer Drive for the ADC?
(Analog Dialogue, Volume 41 February 2007)
"Rules of the Road" for High-Speed Differential ADC Drivers
(Analog Dialogue, Vol. 43, No. 5, 2009)
Maximize Performance When Driving Differential ADCs
... Converting a single-ended signal to a differential signal before the analog-to-digital conversion can improve the performance of your data-acquisition system. By Sally Paterson, Analog Devices (EDN, 6/12/2003)
|High Speed Amplifiers Selection Table (pdf, 77 kB)||Product Selection Guide|
(pdf, 196 kB)
Many Analog Devices products can be purchased as Class K die.
|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|
|AD8138 SPICE Macro-Model||SPICE Models||HTML|
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.