An I/Q-channel time-interleaved bandpass sigma-delta modulator for a low-IF receiver

This brief proposes a multiplexing scheme to realize an I/Q-channel time-interleaved (TI) bandpass sigma-delta modulator that shares operational transconductance amplifiers to minimize power consumption and silicon area for a low-intermediate-frequency (IF) wireless receiver. The test chip was fabricated for a 10.7-MHz IF system with a 0.35-mu m CMOS process. The measured peak signal-to-noise distortion ratio for a 200-kHz bandwidth is approximately 73 dB. The power consumption of the fabricated chip is 61 mW with a 3.3-V supply, and the silicon area is 1.78 mm(2). The measured channel crosstalk is about -48 dB.