Two-path band-pass Δ∑ modulator with 40-MHz IF 72-dB DR at 1-MHz bandwidth consuming 16 mW

A band-pass SigmaDelta modulator that uses two time interleaved second-order modulators and cross-coupled paths is described. Split zeros around the 40-MHz IF provide a signal band of 1 MHz with 72-dB DR and 65.1-dB peak SNR. The circuit, integrated in a 0.18-mum CMOS technology, uses a 60-MHz clock per channel. Experimental results show that the in-band region is not affected by tones caused by mismatches and that a two-tones input causes an IMD signal of 68 dBc. The power consumption is 16 mW with 1.8-V supply.