Communications infrastructure, imaging equipment, industrial instrumentation, defence electronics and other multi-channel, data-hungry systems require wider resolutions and higher sampling rates from the data conversion stage. Physical layout constraints of the parallel interface and bit-rate limitations of the serial LVDS (low-voltage differential signalling) have started to present technical barriers for designers.
In response Analog Devices has introduced the AD9250 dual-channel, 14-bit, 250-MSP A/D converter featuring the JEDEC JESD204B serial output data interface standard. The AD9250 A/D converter is the first-to-market with full JESD204B Subclass 1 deterministic latency at 250 MSPS. This functionality accommodates the precise synchronisation of multiple data-conversion channels through a serial interface.
The AD9250 A/D converter’s serial interface implementation provides up to 5 Gbps over a 1 or 2 lane-capable link. Two serial lanes are used to support the full 250-MSPS, dual A/D converter data rate, or a single lane can be used to support reduced sampling rates.
High-performance FPGA suppliers, such as Xilinx, have incorporated on-chip JESD204B SerDes (serialiser/deserialiser) ports into their latest generation products. This end-to-end seamless connectivity for the analogue signal chain results in simplified PCB layout, rapid prototyping capability, and faster time-to-market.
“Xilinx is fully-committed to supporting the JEDEC JESD204B standard and is striving to accelerate adoption of the serialised interconnect technology for data converters. We are doing this by providing high quality, flexible, scalable and programmable IP to interface with high speed data converters like the AD9250,” said Sunil Kar, senior director, Wireless Business Group at Xilinx. “Xilinx currently provides JEDEC JESD204B IP for Subclass 0, 1 and 2 functionality, with line rates up to 10.3 GBPS and lane widths ranging from x1 to x8 on our devices. This combination of technology advancements improves system modularisation, lowers cost and complexity and will enhance the capabilities and capacities of next generation wireless and wired networks.”
“This flagship product from Analog Devices signals a new, tightly integrated approach to designing the analogue signal chain in FPGA-based systems,” said Kevin Kattmann, product line director, High-speed A/D Converters at Analog Devices. “The AD9250 dual 14-bit A/D converter delivers unmatched wideband signal processing performance while its simplified interface breaks design barriers for next-generation FPGA-based applications in software-defined radio and medical ultrasound. For many system designers, the I/O challenge in implementing the high-performance analogue signal chain now has an elegant solution.”
The AD9250 converter’s JESD204B serial interface reduces the number of high-speed differential output data paths required from as many as 28 to just two per IC. Its Subclass 1 deterministic latency function is repeatable from power-up cycle to power-up cycle and across link re-synchronisation events. Areas where this function is important are in diversity radio systems and instrumentation, multi-mode digital receiver applications such as TD-SCDMA, WCDMA, LTE (especially the 2R2T >8R8T evolution), radar/defence electronics, medical imaging systems, cable infrastructure and general-purpose software radios.