| PhD Seminar

Name of the Speaker: Mr. Chaitanya Kumar (EE19D752)
Guide: Dr. Shanthi Pavan
Venue: ESB-244 (Seminar Hall)
Online meeting link: https://meet.google.com/aeo-fqyc-mvq
Date/Time: 2nd January 2025 (Friday), 11:30 AM
Title: Analysis and Design of Continuous-Time Pipeline ADCs with Bandpass STF

Abstract :

Continuous-time pipeline ADCs (CTPs) represent a shift in how high-speed analog-to-digital conversion can be approached. By combining inherent anti-aliasing, open-loop high-speed operation, and an easy-to-drive input impedance, CTPs fundamentally reduce reliance on power-hungry input buffers and complex front-end filtering. These attributes position CTPs as a scalable and energy-efficient foundation for future wideband data-conversion systems.

Extending this paradigm to bandpass signal acquisition, this work introduces the bandpass continuous-time pipeline ADC (BPCTP) as a new and powerful member of the CTP family. Rather than treating filtering and digitization as separate blocks, the BPCTP merges them into a single architecture with a precisely controlled signal transfer function. By avoiding feedback-loop operation, the BPCTP eliminates stringent latency constraints on the quantizer, enabling higher speeds and wider bandwidths than are practical with traditional bandpass continuous-time delta-sigma modulators.

The concept is validated through a fabricated three-stage BPCTP in 65 nm CMOS, demonstrating 800 MS/s operation over a 50 MHz bandwidth with a peak SNDR of 68.5 dB. The prototype behaves like a high-order bandpass filter followed by a high-resolution ADC, yet achieves this using a modest-resolution backend converter, leveraging inter-stage gain inherent to the pipeline. Beyond the analog front end, the architecture seamlessly integrates digital reconstruction, demodulation, and decimation, pointing toward highly compact and power-efficient receiver implementations.

Together, the analysis and silicon results establish the BPCTP as a compelling and scalable architecture for next-generation RF and IF receivers.