Tutorial: Wideband Delta Sigma Modulators

The application space of delta-sigma analog-to-digital converters has been greatly extended during the last few decades with applications ranging from traditional applications such as audio and hearing aids that require only a few (tens of) kHz bandwidth to a multitude of cellular standards that need up to 40MHz bandwidth. To enable this bandwidth range of four orders of magnitude, new innovative wideband delta-sigma architectures and circuits have been developed that operate at GHz rate sampling frequencies. This tutorial gives an introduction to the system design and implementation of wideband delta-sigma modulators. A review of wideband delta-sigma architectures, loop stability, filter implementations and circuit designs is presented. Some case studies illustrate wideband delta-sigma modulators that have bandwidths in the range from several tens of MHz to beyond 100MHz.