A 180 nm CMOS Integrated System based on a Multilevel Synchronized Pulsed Modulation for High Efficiency Implantable Optical Biotelemetry

Abstract

This paper reports on the design of a fully integrated UWB-inspired optical biotelemetry system for high efficiency implantable devices in biomedical applications. The communication link implements a multilevel data coding combined to a synchronized pulse position modulation technique operating with serial bitstreams having data rates from 60 Mbps to 240 Mbps and symbols composed by 1 up to 6 bits (configurable operating modes). The optical biotelemetry system takes advantage of the use of 300 ps laser pulses as the data transmitter and of a Si photodiode as the data receiver so guaranteeing reliable operations, wide bandwidth, high efficiency, electromagnetic compatibility, and signal integrity. The proposed system has been designed in TSMC 180 nm standard CMOS technology requiring a total Si area of about 0.044 mm2. Post-layout simulations demonstrate the correctness of the system functionalities and operations for transmission data rates up to 240 Mbps, symbol lengths up to 6 bits, and overall energy efficiencies lower than 22 pJ/bit. The comparison with results of similar solutions in the Literature demonstrates that the proposed system achieves the best performances in terms of data rate and energy efficiency.