A 56 GS/s 8 Bit Time-Interleaved ADC in 28 nm CMOS

Abstract

This paper presents a real-time output 56 GS/s 8 bit time-interleaved analog-to-digital converter (ADC), where the full-speed converted data are output by 16-lane transmitters. A 64-way 8 bit asynchronous SAR array using monotonous and split switching strategy with 1 bit redundancy is utilized to achieve a high linearity and high-power efficiency. A low-power ring voltage-controlled oscillator-based injection-locked phase-locked loop combining with a phase interpolator-based time-skew adjuster is developed to generate the 8 equally spaced sampling phases. Digital gain correction, digital-detection-analog-correction offset calibration, and coarse–fine two-step time-skew calibration are combined to optimize the ADC’s performances. An edge detector and phase selector associated with a common near-end data-transmission position and far-end data-collection instant are designed to avoid reset competition and implement deterministic latency. Fabricated in a 28 nm CMOS process, the prototype ADC achieves an outstanding SNDR of 36.38 dB at 56 GS/s with a 19.9 GHz input, where 7.25 dB and 9.33 dB are optimized by offset-gain calibration and time-skew calibration, respectively. The ADC core occupies an area of 1.2 mm2 and consumes 432 mW power consumption.

Coherent General-Purpose Photonic Matrix Processor

“…With a 5 GBd symbol rate, the overall throughput reaches 30 giga operations per second, highlighting the advantage of photonic computing in speed. Given the state-of-the-art electronic integrated circuit technology, ADC with four channels at the 56 GBd symbol rate is readily available, 39 matching the throughput of 4 × 4 photonic matrix-vector multiplication. This enables a single photonic core running at a throughput of 0.4 tera operations per second (TOPS), 1 order of magnitude higher than the state-of-the-art digital processors or accelerators.…”

A 17 GHz inductorless low‐pass filter based on a quasi‐Sallen–Key approach

“…The growing diffusion of ultrawideband communication systems and very high frequency measurement systems has led to the development of analog-to-digital (ADC) [1][2][3] and digital-to-analog (DAC) 4,5 converters operating at tens of GHz sample rate. Such converters require low-pass filters, to be used as anti-aliasing and shaping filters, with a bandwidth from dc to 10 GHz and beyond.…”