A 63-mA 112/94-dB DR IF bandpass ΔΣ modulator with direct feed-forward and double sampling

Abstract

We developed a 10.7-MHz intermediate frequency (IF) bandpass discrete-time (DT) 4^th -order 4-bit ΔΣ modulator for AM/FM car radio tuners. Using direct feed-forward and double sampling, we have achieved a dynamic range (DR) of 112 dB in the 3-kHz AM bandwidth (BW) and a DR of 94 dB in the 200-kHz FM BW. The modulator occupies 3 mm², in 0.15 μm CMOS technology, and draws 63 mA of current.