
Switched-Capacitor Data Converters
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As a fi nal note, although multibit quantizers have been seen mostly in cascaded
modulators so far, they can also be employed to build single-stage modulators. A
practical example is a multibit audio ∆Σ DAC that was built based on the third-order
DQIR topology shown in Figure 5.19 [79].
Note that there are many ∆Σ modulator topologies other than the ones presented
here. For example, the band-pass ∆Σ modulator is a subject of many ongoing
research activities in the community of analog and RF circuit designers at the time
of this writing, mainly due to its great potential in wireless communications. Very
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