Features and Benefits
- Easy to use, single-ended-to-differential conversion
- Adjustable output common-mode voltage
- Externally adjustable gain
- Low harmonic distortion
-94 dBc SFDR at 5 MHz
-85 dBc SFDR at 20 MHz
- -3 dB bandwidth of 320 MHz, G = +1
- Fast settling to 0.01% of 16 ns
- Slew rate 1150 V/µs
- Fast overdrive recovery of 4 ns
- Low input voltage noise of 5 nV/√Hz
- See data sheet for additional features
- Download AD8138-EP data sheet (pdf)
- Extended temperature range: −55ºC to +105°C
- Controlled manufacturing baseline
- One assembly/test site
- One fabrication site
- Enhanced product change notification
- Qualification data available on request
- V62/12665-01XE DSCC Drawing Number
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 the proprietary ADI 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 differential output of the AD8138 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 high bandwidth and IP3 of the AD8138 also make it appropriate for use as a gain block in IF and baseband signal chains. The AD8138 offset and dynamic performance makes 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).
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
The Universal Differential Amplifier Evaluation Boards can be used to evaluate single, high speed, fully differential amplifiers. The evaluation boards are bare boards that enable users to quickly prototype a variety of differential or single-ended circuits, which minimizes risk and reduces time to market. These boards are all RoHs Compliant. See references below on what board to order by lead count and package.
Documentation & Resources
AN-1516: 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 (Rev. C)12/21/2017
AN-1500: 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 (Rev. B)11/29/2017
AN-1501: DC-Coupled, Single-Ended to Differential Conversion Using the AD8138 Low Distortion Differential ADC Driver and the AD7356 5 MSPS, 12-Bit SAR ADC (Rev. C)11/28/2017
AN-0990: Terminating a Differential Amplifier in Single-Ended Input Applications (Rev. 0)2/14/2015
AN-0992: Active Filter Evaluation Board for Differential Amplifiers (Rev. 0)2/14/2015
AN-589: Ways to Optimize the Performance of a Difference Amplifier (Rev. B)2/14/2015
AN-1026: High Speed Differential ADC Driver Design Considerations (Rev. A)2/14/2015
AN-584: Using the AD813X Differential Amplifier (Rev. 0)10/14/2002
High Speed Amplifiers Selection Table2/27/2008
Simple Circuit Provides Adjustable CAN-Level Differential-Output Signal4/1/2012 Analog Dialogue
"Rules of the Road" for High-Speed Differential ADC Drivers5/1/2009 Analog Dialogue
Ask The Application Engineer—36: Wideband A/D Converter Front-End Design Considerations II: Amplifier-or Transformer Drive for the ADC?2/1/2007 Analog Dialogue
Maximize Performance When Driving Differential ADCs6/12/2003
Design a Logamp RF Pulse Detector1/1/2000
Tools & Simulations
Precision ADC Driver Tool
The Precision ADC Driver Tool is a web application that simulates the performance of precision ADC and driver combinations. Potential issues with driver selection, kickback settling, and distortion are flagged, and design tradeoffs can be quickly evaluated. Simulations and calculations include system noise, distortion, and settling of the ADC input
Sys-Parameter models contain behavioral parameters, such as P1dB, IP3, gain, noise figure and return loss, which describe nonlinear and linear characteristics of a device.
ADIsimRF is an easy-to-use RF signal chain calculator. Cascaded gain, noise, distortion and power consumption can be calculated, plotted and exported for signal chains with up to 50 stages. ADIsimRF also includes an extensive data base of device models for ADI’s RF and mixed signal components.
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.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
|Part Number||Material Declaration||Reliability Data||Pin/Package Drawing||CAD Symbols, Footprints & 3D Models|
|AD8138ACHIPS||Material Declaration||Reliability Data||None Available|
|AD8138ARMZ||Material Declaration||Reliability Data||8-Lead MSOP|
|AD8138ARMZ-REEL||Material Declaration||Reliability Data||8-Lead MSOP|
|AD8138ARMZ-REEL7||Material Declaration||Reliability Data||8-Lead MSOP|
|AD8138ARZ||Material Declaration||Reliability Data||8-Lead SOIC|
|AD8138ARZ-R7||Material Declaration||Reliability Data||8-Lead SOIC|
|AD8138ARZ-RL||Material Declaration||Reliability Data||8-Lead SOIC|
|AD8138SRMZ-EP-R7||Material Declaration||Reliability Data||8-Lead MSOP|
|Wafer Fabrication Data|
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Sample & Buy
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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.