J. Hauptmann

A low-noise amplifier with automatic gain control and anticlipping control in CMOS technology

A CMOS low noise amplifier with two automatic gain control loops is presented. Automatic gain control is performed by the use of linearized MOS resistive circuits as voltage controlled resistors. By the use of parasitic lateral bipolar transistors in the input stage, the equivalent input noise is 14nV/¿Hz and free from 1/f noise in the voiceband. Integrated in a 2 ¿m CMOS process the circuit has an active area of 0,8 mm2.

A software programmable CMOS telephone circuit

A mixed Analog-Digital IC combining the speech and signalling functions for an analog telephone on a 2¿ CMOS chip will be described. New features such as software programmable level control, dc characteristics, input impedance and transhybrid balancing offer a flexible system-solution for the different international requirements with a minimum number of external components. This features enable telephone manufacturers to produce a quality feature phone with a minimum number of components, and therefore with high reliability and low cost.

A four-channel CMOS codec filter circuit "SICOFI-4"

Cost reduction by integration of complex mixed analog-digital systems on a single chip and an excellent yield to area ratio is a major goal for IC design in the nineties. In this paper, a four-channel codec-filter chip for analog subscriber lines in ISDN-orientated networks is presented, giving an exceptional example for high level system implementation combined with parallel DSP integration and analog circuitry with high performance. The chip combines four analog frontends, digital signal processing realized by different approaches for a sophisticated filter concept in addition with test strategies including digital and analog BIST. The circuit is fabricated in a standard 1-/spl mu/m CMOS technology, needs a single 5-V power supply, and can easily be programmed to world-wide different country specifications and applications. >