16b Third-order Sigma Delta Modulator With Reducedsensitivity To Nonidealities

Early work on third-order modulators used a cascade offirstorder loops to insure stability and achieve the theoretically-expected performance at the expense of extreme component matching and op amp gain requirements. 1.2 Third or higher-order modulators implemented in a single loop typically display lower sensitivity at the expense of conditional stability .3 This paper presents a cascade of a second- and first-order loop which insures unconditional stability while achieving the theoretically-expected performance in the presence of practical nonidealities.