English
Sign In[Non-Member]
| 1-5hit |
Retdian Agung NICODIMUS Shigetaka TAKAGI
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.
Retdian A. NICODIMUS Shigetaka TAKAGI Kazuyuki WADA
An active shield circuit which effectively reduces the substrate noise on the entire area inside the guard ring regardless of the noise source position is proposed. Simulation result shows that the proposed circuit can reduce the noise level to -85 dB while a conventional guard ring gives -52 dB.
Retdian A. NICODIMUS Hiroto SUZUKI Kazuyuki WADA Shigetaka TAKAGI
A design optimization of active shield circuit using noise averaging method is proposed. The relation between the averaged noise and the design parameters of the active shield circuit such as circuit gain and on-chip layout is examined. A simple design guideline is also provided. Simulation results show that the active shield circuit designed by the proposed optimization method gives a better noise suppression performance of about 28% than the conventional one.
Keiko Makie-FUKUDA Toshiro TSUKADA
This paper describes fully integrated active guard band filters for suppressing the substrate coupling noise and their noise suppression effect measured by test chip experiments. The noise cancellation circuit of the active guard band filters simply consists of an inverter and a source follower. The substrate noise suppression effect was measured by using a test chip fabricated in a 0.18 µm CMOS triple-well process for system-on-a-chip. The noise with the filter was less than 5% of that without the filter and the noise suppression effect was observed from 1 MHz to 200 MHz by the statistical measurement of the voltage comparator. The noise suppression effect was also observed for actual digital switching noise produced by digital inverters. Configuration of the active guard band filter was investigated by simulation and it is shown that high and uniform noise suppression effect is achieved by placing the guard bands in the L-shape around the target triple-well area on the p-substrate.
Keiko Makie-FUKUDA Toshiro TSUKADA
An AC coupling configuration for the active guard band filters is introduced for suppressing substrate coupling noise in analog and digital mixed-signal integrated circuits. With this method, a substrate-coupling-noise cancellation signal can be supplied to a ground-level substrate by using a single 3-V supply on-chip circuits. Noise was suppressed to a maximum of less than 0.05 from 100 Hz to 2 MHz in a 0.35-µm CMOS test chip. Both experiments and a simulation based on the substrate extraction model showed the similar dependence of the noise-suppression effect on the arrangement of the guard-bands and analog circuits. The simulation is thus effective for optimizing the arrangement to suppress noise effects when designing a chip.
English
