This paper describes an original solution for improving inductive contactless telemetry powered devices. Rather than implementing asynchronous logic to provide digital circuit performance, we propose to apply the asynchronous logic paradigm to the whole system, providing high data rates, low power consumption on tags and dynamic performance adaptation. This flexibility allows a dynamic compromise between performance, power consumption and data rate, according to environmental conditions. To achieve this, the contactless system is based on asynchronous event-based communication and a tag architecture that is self-adaptive to data rate. This paper describes the communication scheme and selfadaptive to data rate front-end architecture which were validated on silicon. Test chip implementation and results are given, showing that any communication, up to 1.02 Mbps, is demodulated up to 6 cm from its reader with a power consumption on tag below 100 ?W.