Design of Active Shield Circuit with Automatic Tuning Scheme

Retdian Agung NICODIMUS  Shigetaka TAKAGI  

IEICE TRANSACTIONS on Electronics   Vol.E88-C   No.6   pp.1196-1202
Publication Date: 2005/06/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.6.1196
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit and Device Technologies)
Category: Mixed Signal
digital noise,  substrate coupling,  active noise cancellation,  active shield circuit,  mixed-signal integrated circuits,  

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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 12 dB.