Retdian A. Nicodimus

Multi-Path Analog Circuits Robust to Digital Substrate Noise

A multi-path structure is proposed for reduction in effect of digital substrate noise which degrades analog circuit performance. As an example low-pass filters are implemented in a 0.18-μm CMOS process. 11-dBm reduction in digital substrate noise is achieved as compared with a conventional structure.

Reduction of Bootstrapped Switch Area Consumption Using Pre-Charge Phase

This paper discusses the input range limitation problem in a track-and-hold circuit and the compensation method using a bootstrapped switch. A bootstrapped switch with an additional control circuit is proposed to compensate charge loss in conventional bootstrapped switch circuit. Simulation results using 0.18-μm CMOS process parameters show that the proposed circuit reduces the bootstrap capacitance down to 25% for the conventional circuit.

Design of Active Shield Circuit with Automatic Tuning Scheme

A feedforward-based active shielding technique for digital noise suppression is more preferred for its capability of reducing the noise on the entire area inside the guard ring. In order to compensate for the variation of substrate parameters, an automatic control scheme to tune the gain of the active shield circuit is proposed. Simulation results show the effectiveness of the proposed system in reducing the digital noise regardless of circuit layout. Simulation results also show that noise suppression improvement from passive guard ring to active shield with tuning is 20 dB or one tenth while that from active shield without tuning to active shield with tuning is 12dB.