A 2.5MHz 55dB switched-current bandpass #SIGMA# #DELTA# modulator for AM signal conversion

摘要

We present a Switched-Current (SI) fourth-order bandpass #SIGMA# #DELTA# modulator IC prototype. It uses fully-differential circuits in 0.8#mu#m CMOS technology to obtain a Dynamic Range (DR) larger than 55dB at 2.5MHz center frequency with 30kHz bandwidth-in accordance to the requirements of AM digital receivers. The prototype incorporates a single-ended to fully-differential current-mode buffer for testing purposes. The power consumption of the whole prototype (modulator plus buffer) is 60mW from a 5V supply voltage.