Title :
A 0.25-mW low-pass passive sigma-delta modulator with built-in mixer for a 10-MHz IF input
Author :
Chen, Feng ; Leung, Bosco
Author_Institution :
Circuit Technol. Lab., Texas Instrum. Inc., Dallas, TX, USA
fDate :
6/1/1997 12:00:00 AM
Abstract :
The design of a passive sigma-delta modulator without using operational amplifiers is presented. Issues of its application to IF digitization with subsampling scheme are discussed. In addition, a switch-only gain-boost network is proposed to achieve a dc voltage gain in a passive way. The prototype chip of a second-order passive sigma-delta modulator was fabricated in a 1.2-μm CMOS process. Testing results showed that with a 10-MHz IF input (bandwidth of 20 kHz), the modulator achieved a 13-b resolution at 0.25 mW with a 3.3 V power supply. Good performance was also measured with a baseband input
Keywords :
CMOS integrated circuits; mixers (circuits); passive networks; sigma-delta modulation; 0.25 mW; 1.2 micron; 10 MHz; 20 kHz; 3.3 V; CMOS process; IF digitization; IF input; baseband input; built-in mixer; dc voltage gain; low-pass passive sigma-delta modulator; subsampling scheme; switch-only gain-boost network; Bandwidth; Baseband; CMOS process; Delta-sigma modulation; Operational amplifiers; Power supplies; Prototypes; Semiconductor device measurement; Testing; Voltage;
Journal_Title :
Solid-State Circuits, IEEE Journal of
