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AD9261:  16-Bit, 10 MHz Bandwidth, 30 MSPS to 160 MSPS Continuous Time Sigma-Delta ADC

Product Details

The AD9261 is a 16-bit analog-to-digital converter (ADC) based on a continuous time sigma-delta (Σ-Δ) architecture that achieves 86 dB of dynamic range over a 10 MHz input bandwidth. The integrated features and characteristics unique to the continuous time Σ-Δ architecture significantly simplify its use and minimize the need for external components.

The AD9261 has a resistive input impedance that significantly relaxes the requirements of the driver amplifier. In addition, a 32× oversampled 5th-order continuous time loop filter significantly attenuates out of band signals and aliases, reducing the need for external filters at the input.

An external clock input or the integrated integer-N PLL provides the 640 MHz internal clock needed for the oversampled continuous time Σ-Δ modulator. On-chip decimation filters and sample rate converters reduce the modulator data rate from 640 MSPS to a user-defined output data rate between 30 MSPS to 160 MSPS, enabling a more efficient and direct interface.

The digital output data is presented in offset binary, Gray code, or twos complement format. A data clock output (DCO) is provided to ensure proper timing with the receiving logic.

The AD9261 operates on a 1.8 V analog supply and a 1.8 V to 3.3 V digital supply, consuming 375 mW. The AD9261 is available in a 48-lead LFCSP and is specified over the industrial temperature range (−40°C to +85°C).

Product Highlights

  1. Continuous time Σ-Δ architecture efficiently achieves high dynamic range and wide bandwidth.
  2. Passive input structure reduces or eliminates the requirements for a driver amplifier.
  3. An oversampling ratio of 32× and high order loop filter provide excellent alias rejection reducing or eliminating the need for antialiasing filters.
  4. An integrated decimation filter, sample rate converter, PLL clock multiplier, and voltage reference provide ease of use.
  5. Operates from a single 1.8 V analog power supply and 1.8 V to 3.3 V output supply.
  6. A standard serial port interface (SPI) supports various product features and functions.


  • Data Acquisition
  • Automated Test Equipment
  • Instrumentation
  • Medical Imaging


  • SNR: 83 dB (85 dBFS) to 10 MHz input
  • SFDR: 87 dBc to 10 MHz input
  • Noise figure: 15 dB
  • Input impedance: 1 kΩ
  • Power: 340 mW
  • 1.8 V analog supply operation
  • 1.8 V to 3.3 V output supply
  • Selectable bandwidth 2.5 MHz/5 MHz/10 MHz
  • Output data rate: 30 MSPS to 160 MSPS
  • Integrated decimation filters
  • Integrated sample rate converter
  • On-chip PLL clock multiplier
  • On-chip voltage reference
  • Offset binary, Gray code, or twos complement data format
  • Serial control interface (SPI)

Functional Block Diagram for AD9261


Title Content Type File Type
AD9261: 16-Bit, 10 MHz Bandwidth, 30 MSPS to 160 MSPS Continuous Time Sigma-Delta ADC Preliminary Data Sheet (Rev 0, 04/2010) (pdf, 105 kB) Data Sheets PDF
AN-1142: Techniques for High Speed ADC PCB Layout  (pdf, 392 kB) Application Notes PDF
AN-878: High Speed ADC SPI Control Software  (pdf, 585 kB) Application Notes PDF
AN-282: Fundamentals of Sampled Data Systems  (pdf, 2131 kB) Application Notes PDF
AN-807: Multicarrier WCDMA Feasibility  (pdf, 969 kB) Application Notes PDF
AN-808: Multicarrier CDMA2000 Feasibility  (pdf, 1535 kB)
The goal of this application note is to determine the feasibility of implementing a multicarrier CDMA2000 transceiver and what the major subsystem performances must be.
Application Notes PDF
AN-877: Interfacing to High Speed ADCs via SPI  (pdf, 1594 kB) Application Notes PDF
AN-905: VisualAnalog Converter Evaluation Tool Version 1.0 User Manual  (pdf, 2124 kB) Application Notes PDF
AN-835: Understanding High Speed ADC Testing and Evaluation  (pdf, 985 kB) Application Notes PDF
AN-812:  MicroController-Based Serial Port Interface (SPI) Boot Circuit (pdf, 452,449 bytes)  (pdf, 441 kB)
This application note describes the operation of a general-purpose, microcontroller-based Serial Port Interface (SPI) boot circuit.
Application Notes PDF
AN-283: Sigma-Delta ADCs and DACs  (pdf, 1699 kB)
Overview of Sigma-Delta Concepts: Oversampling, Noise Shaping Using the Sigma-Delta Modulator, Digital Filtering and Decimation.
Application Notes PDF
MS-2210: Designing Power Supplies for High Speed ADC  (pdf, 327 kB) Technical Articles PDF
Understanding Continuous-Time, Discrete-Time Sigma-Delta ADCs And Nyquist ADCs
Due to the high performance, efficiency, and ease of use of the CT-ΣΔ architecture, manufacturers of high-performance analog-to-digital converters (ADCs) are now bringing this converter architecture to market as a standard product.
(Electronic Design, February 20, 2009)
Technical Articles HTML
AD926x Family 16-Bit, 10 MHz Bandwidth, Continuous-Time Sigma-Delta (CTSD) Analog-to-Digital Converters  (pdf, 1406 kB) Overview PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
ADIsimADC is Analog Devices' Analog-to-Digital Behavioral Model that accurately models the typical performance characteristics of many of our High Speed Converters. The model faithfully reproduces the errors associated with both static and dynamic features such as AC linearity, clock jitter, and many other product specific anomalies.
ADIsim Design/Simulation Tools 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.

Product Recommendations & Reference Designs

Companion Products

Suggested Companion Products

Recommended ADC Drivers for the AD9261

  • For differential inputs requiring low noise and high linearity, we suggest the ADA4937-1 or the ADA4932-1.
Recommended Clock Drivers for the AD9261 Recommended External Reference for the AD9261
  • For improved thermal drift and gain accuracy, we recommend the ADR130 (1V reference).
Recommended Power Solutions
  • For selecting voltage regulator products, use ADIsimPower.

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Price, packaging, availability

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.

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