TABLE OF CONTENTS The trend in ADCs and DACs is toward higher speeds and higher resolutions at reduced power levels. Modern data converters generally operate on 5 V (dual supply) or +5 V (single supply). In fact, many new converters operate on a single +3 V supply. This trend has created a number of design and applications problems which were much less important in earlier data converters, where 15 V supplies and 10 V input ranges were the standard.
Lower supply voltages imply smaller input voltage ranges, and hence more susceptibility to noise from all potential sources: power supplies, references, digital signals, EMI/RFI, and probably most important, improper layout, grounding, and decoupling techniques. Single-supply ADCs often have an input range which is not referenced to ground. Finding compatible single-supply drive amplifiers and dealing with level shifting of the input signal in direct-coupled applications also becomes a challenge.
In spite of these issues, components are now available which allow extremely high resolutions at low supply voltages and low power. This section discusses the applications problems associated with such components and shows techniques for successfully designing them into systems.
The most popular precision signal conditioning ADCs are based on two fundamental architectures: successive approximation and sigma-delta. The tracking ADC architecture is particularly suited for resolver-to-digital converters, but it is rarely used in other precision signal conditioning applications. The flash converter and the subranging (or pipelined) converter architectures are widely used where sampling...
