Wideband ADCs drive applications to direct-RF sampling

Wideband ADCs drive applications to direct-RF sampling

New Products |
By eeNews Europe

The parts feature a range of integrated functions to help you exploit their performance, and to simplify their use; the “breakthrough performance, bandwidth, and integrated functionality” will drive applications further towards direct-RF sampling, ADI asserts.

AD9680 is a dual-channel, 1.25-V,14-bit, 1-Gsample/s A/D converter featuring the best noise and dynamic range performance in its class enabling the trend for direct RF sampling in communications, instrumentation and military/aerospace applications. Its noise density of -154 dBFs/Hz is the lowest in the industry.

Wideband RF data acquisition allows for better signal extraction in congested RF environments, over a wider bandwidth; the device also features four digital down-converters to assist with isolating a specified fraction or subset of the overall bandwidth. The AD9680 is interoperable with FPGAs from major manufacturers and supported with known good configurations, and offers ease of interfacing.

The AD9680, ADI says, allows more degrees of freedom for system designers trading off signal bandwidth, noise and linearity because it can digitise a DC to 2-GHz input signal with an accompanying dynamic range performance that was previously unavailable on the open market. You can increase signal sensitivity and bandwidth data rate, while enabling the use of an advanced reconfigurable data acquisition or radio platform. The A/D converter is available with an evaluation board design environment and reference designs for rapid system prototyping and board-level design and layout.

The AD9680 was designed for sampling wide bandwidth analogue signals up to 2 GHz with best-available dynamic range and noise performance over its rated bandwidth range. When converting a 1-GHz input, the converter achieves spurious-free dynamic range (SFDR) performance of 80-dBc and 61.5-dBFS signal-to-noise ratio (SNR) while consuming 1.65 W of total power per channel. Integrated functionality includes digital signal processing blocks and a configurable JESD204B interface, allowing designers to create advanced reconfigurable radio platforms that meet bandwidth and cost requirements across multiple systems. Higher speed grades are scheduled. On-chip features support signal monitoring and threshold detection prior to the signal being passed to an FPGA, speeding reaction and reducing the digital processing load.

Each GSPS A/D converter is supported by an evaluation board with an FPGA Mezzanine Card (FMC) connector, software, tools, SPI controller and reference designs. The company’s VisualAnalog software package combines a set of simulation and data analysis tools with a graphical interface allowing designers to customize their input signal and data analysis. The high-speed A/D converter SPI controller tool allows users to control advanced features with SPI capability. An industry-first, data capture board supporting JESD204B lane rates at 12.5 Gbps is also available; the part supports four configurable lanes.

Also announced by ADI is the AD9625 that, “combines high bandwidth with industry-leading dynamic range and noise for first time in a 2-GSPS data converter to drive applications to direct RF sampling.”

This part is a 12-bit, 2-Gsample/s, AD9625 A/D converter. It provides the best noise and dynamic range performance in its class for better receiver sensitivity along with the ability to discern smaller signals in the presence of noise, clutter, blockers and interferers. This performance combined with 2-Gsample/sec bandwidth and integrated signal processing functionality enables the trend to direct RF sampling in communications, instrumentation and military/aerospace applications. The converter’s noise spectral density of 149.5 dBFS/Hz, coupled with high-input bandwidth, allow designers to use undersampling system architectures into the 2nd Nyquist zone, saving on a frequency down-conversion stage.

An ADI spokesman confirmed that the 9265 – a single channel part – is not a variant of the 9680, interleaving the two channels of the 9680, but is a completely separate design. It shares features with the 9680, in that it also has additional on-chip functionality for ease-of-use, such as digital-down-conversion to select a subset of the input bandwidth; and the JEDEC JESD204B interfacing capability.

“In high-speed conversion, sampling rate is important, but it isn’t the only thing we consider in our designs—and it isn’t always the most important figure of merit,” said John Forinash, engineering vice president, Integrated Solutions, Rincon Research Corporation, a leading provider of advanced digital signal processing solutions and technologies to the government. “Wide analogue input bandwidth, improved dynamic range, and noise power ratio performance are also important considerations as we enable systems to collect and process a wider swathe of RF signal bandwidth.”

The AD9625’s wider input bandwidth enables advanced RF sampling architectures and allows designers to reduce the number of analogue frequency down-conversion stages and their associated noise and cost contributions. The simplified system architecture eliminates the need to interleave multiple A/D converters to obtain needed performance and allows for development of reconfigurable platforms. It is available with an evaluation board design environment and reference designs to simplify system prototyping and board-level design and layout.

The AD9625 achieves 80-dBc spurious-free dynamic range (SFDR) with a 1-GHz input. The AD9625 is, ADI claims, the only open-market-available 12-bit, 2-Gsample/sec, A/D converter that simplifies the digital interfacing challenge by integrating two digital-down converters (DDC), two numerically controlled oscillators (NCO) and a configurable JESD204B serial link for the output data.

Key applications include ultra-wideband RADAR, wideband front-ends for digital storage oscilloscopes and data acquisition platforms.

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