Title :
An efficient CMOS line driver for 1.544-Mb/s T1 and 2.048-Mb/s E1 applications
Author_Institution :
Adv. Commun. Products, EXAR Corp., Fremont, CA, USA
fDate :
2/1/2003 12:00:00 AM
Abstract :
A CMOS operational amplifier (OPAMP) for use as a line driver for high-speed T1/E1 data communication link is described. The differential output swing, using a single 3.3-V power supply, is 5.2-V peak-to-peak on a 20-Ω load. Novel circuits are used to control the closed-loop output impedance, quiescent bias current, and frequency compensation to ensure stable operation over varying temperature and load conditions. A special circuitry tristates the output in case of power-supply failure. The OPAMP achieves a unity-gain bandwidth of 35 MHz with only 10 mA of quiescent current. A new output-current-sense circuitry is used to provide a current feedback to adjust the output impedance for proper line termination as well as to provide short-circuit protection from excessive output currents. Using 0.35-μm n-well CMOS technology, the amplifier occupies 0.69 mm2 of area.
Keywords :
CMOS analogue integrated circuits; circuit stability; compensation; data communication equipment; driver circuits; electric current control; electric impedance; feedback amplifiers; operational amplifiers; overcurrent protection; 0.35 micron; 1.544 Mbit/s; 10 mA; 2.048 Mbit/s; 3.3 V; 35 MHz; CMOS line driver; CMOS opamp; CMOS operational amplifier; T1/E1 line drivers; closed-loop output impedance control; current feedback; frequency compensation; high-speed T1/E1 data communication link; line termination; n-well CMOS technology; output tristating circuit; output-current-sense circuitry; quiescent bias current control; short-circuit protection; stable operation; varying load conditions; varying temperature conditions; Bandwidth; CMOS technology; Communication system control; Data communication; Driver circuits; Frequency; Impedance; Operational amplifiers; Power supplies; Temperature control;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2002.807413
