An IF-to-Baseband /6/1Modulator for AM/FM/IBOC Radio Receivers With a 118 dB

Abstract

A single-bit fifth-order complex continuous-time IF-to-baseband /6/1 modulator for AM/FM/IBOC receivers is presented. The input IF is 10.7 MHz and the sampling frequency is 41.7 MHz. The modulator achieves a dynamic range of 118 dB in AM mode (3 kHz BW), 98 dB in FM mode (200 kHz BW), and 86 dB in IBOC mode (500 kHz BW). The modulator’s high dynamic range enables the realization of an AM radio receiver without a VGA and without an AM channel-selection filter, thereby reducing system complexity and cost. The elimination of the VGA also improves the sensitivity and the overall noise figure of the receiver. The modulator’s spurious free dynamic range is 88 dB in the bandwidth from 25 to 525 kHz. The IM2 distance is 92 dB, and the IM3 distance is 91 dB. The ADC was fabricated in a one-poly five-metal 0.18- m CMOS process with an active area of 6.0 mm/50. It consumes 210 mW from a 1.8-V supply.