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The first integrator in a low pass continuous-time DeltaSigma modulator normally consumes significant power due to stringent noise and linearity requirements, especially in single-bit designs. We introduce the ldquoassisted opamp integratorrdquo that addresses this problem. The efficacy of our technique is borne out by measurements from a 15 bit audio converter designed in a 0.18 mum CMOS technology. It achieves 92.5 dB dynamic range in a 24 kHz bandwidth and dissipates 110 muW from a 1.8 V supply. The Figure of Merit (FOM) of this modulator is 66.5 fJ/level.