Band connections in active cancellation circuits against digital substrate noise

Band connections employed in active cancellation circuits for effective reduction of digital substrate noise are proposed. An almost-odd-symmetrical noise characteristic is utilized for canceling out noises with different signs outside of a guard ring. Advancing this idea, interlaced connections of four bands are also proposed. Excess cancellation by those bands is more effective for noise reduction in a guard ring than a cancellation by the two bands. Use of L-shaped bands on the basis of the interlaced connection suppresses the noise more. Simulation results show that the proposed band connections reduce the noise