Title :
An analog front end for v.22bis modems
Author :
Hurst, Paul J. ; Glad, Thomas J. ; Illgner, J. Jeff ; Landsburg, George F.
Author_Institution :
Silicon Syst. Inc., Nevada City, CA, USA
Abstract :
An analog front end for the 2400-b/s v.22bis modem has been implemented in a 3- mu m CMOS process. A high level of integration in the front end results in a low-cost, high-performance modem system. A mix of analog switched-capacitor and digital circuits is used throughout the chip. Some of the major functional blocks are a modulator, tone generator, band-split filters, programmable receive gain stage, 8-bit ADC (analog-to-digital converters), bandgap voltage reference, and special signal detectors. Features are included to support a number of lower-speed, split-band modem standards. The chip occupies 59000 mils/sup 2/ and dissipates 200 mW. System and circuit aspects of the design are discussed; measured performance of the IC and of the complete modem system are given.<>
Keywords :
CMOS integrated circuits; linear integrated circuits; modems; 200 mW; 2400 bit/s; 3 micron; 8-bit ADC; CMOS process; analog front end; band-split filters; bandgap voltage reference; high-performance modem system; low-cost; mixed analogue switched capacitor/digital circuits; modulator; monolithic IC; programmable receive gain stage; signal detectors; split-band modem standards; tone generator; v.22bis modems; Analog-digital conversion; CMOS process; Digital circuits; Filters; Modems; Modulation coding; Photonic band gap; Signal generators; Switching circuits; Voltage;
Journal_Title :
Solid-State Circuits, IEEE Journal of
