高速电路设计技巧\sect5

高速电路设计技巧sect5
SECTION 5
HIGH SPEED ADC APPLICATIONS
Walt Kester, Brad Brannon, Paul Hendricks
DRIVING ADC INPUTS FOR LOW DISTORTION AND WIDE
DYNAMIC RANGE
In order to achieve wide dynamic range in high speed ADC applications, careful
attention must be given to the analog interface. Many ADCs are designed so that
analog signals can be interfaced directly to their inputs without the necessity of a
drive amplifier. This is especially true in ADCs such as the AD9220/21/23 family
and the AD9042, where even a low distortion drive amplifier may result in some
degradation in AC performance. If a buffer amplifier is required, it must be carefully
selected so that its distortion and noise performance is better than that of the ADC.

Single-supply ADCs generally yield optimum AC performance when the common-
mode i