A 63 mA 112/94 dB DR IF Bandpass $\Delta\Sigma$ Modulator With Direct Feed-Forward Compensation and Double Sampling

We developed a 10.7 MHz intermediate frequency bandpass discrete-time 4th-order 4-bit DeltaSigma modulator for AM/FM car radio tuners. Using direct feed-forward compensation 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 mum CMOS technology, and draws 63 mA of current.

I. Introduction

AM/FM broadcast radio has been used for over 50 years since the early period of radio broadcasting and is one of the oldest and most popular wireless systems. Even now, most AM/FM radio receivers are analog-based in which all function blocks are analog circuits that handle analog signals, because low cost analog ICs can function as receivers. This is rarely seen in other wireless systems. This is because the high speed, highly functional digital circuitry emerged as silicon transistors were miniaturized, making digital receivers available using digital signal processors (DSPs) or control processing units (CPUs).