Theory and Practical Implementation of a 5th-Order Sigma-Delta A/D Converter
One-bit noise-shaping converters with high-order loop filters have long been considered difficult or impossible to stabilize. In this paper we discuss a new approach that simplifies the analysis of high-order loops, and present several topologies that can be used for the implementation of such loops. An 18-bit A/D converter IC has been designed using this approach that uses a 5th-order loop filter with an unusual loop topology. Implementation of the 5th-order loop filter using differential switched-capacitor techniques is described. A one-step decimation filter with 115 dB stopband attenuation is used to remove out-of-band shaped quantization noise. Preliminary measurements indicate a dynamic range of 105 dB, a number which is compatible with the requirements of professional audio.
Click to purchase paper or login as an AES member. If your company or school subscribes to the E-Library then switch to the institutional version. If you are not an AES member and would like to subscribe to the E-Library then Join the AES!
This paper costs $33 for non-members, $5 for AES members and is free for E-Library subscribers.