Two‐step, piecewise‐linear SAR ADC with programmable transfer function

Abstract

A 7‐bit successive approximation register (SAR) analogue‐to‐digital converter (ADC) with programmable transfer functions is presented. Building upon prior art, a two‐step successive approximation technique is used to implement a piecewise‐linear approximation of the desired transfer function. However, unlike previous implementations of SAR‐based non‐linear ADCs, the proposed work demonstrates programmability of arbitrary non‐linear transfer functions, thus making it suitable for a wide range of low‐bandwidth applications. Simulation results from a proof‐of‐concept design in a standard 180 nm CMOS process are presented to validate the proposed idea.

Keywords

• SAR‐based nonlinear ADCs
• nonlinear transfer functions
• programmable transfer function
• two‐step successive approximation technique
• piecewise‐linear approximation
• successive approximation register analogue‐to‐digital converter