Integration and system design trends of ADSL analog front ends and hybrid line interfaces

System optimization of the Analog Front End (AFE) and hybrid line interface is a key contributor in achieving high data rate and long reach for Asymmetric Digital Subscriber Line (ADSL) modems. Following a brief review of the ADSL system, the basic building blocks in an AFE, analog line interface, and hybrid matching issues are introduced. Integration trends of a single-channel AFE and circuit design challenges for multi-channel AFE are then presented. Line driver technologies and line receiver design issues are discussed with emphasis on the tradeoff between noise and linearity. Finally, design challenges for a highly integrated ADSL modem chipset with minimal external components are addressed.