Patent ID: 8818265

Claim:
A device, comprising: a first substrate in a first voltage domain; a second substrate in a second voltage domain; a transmitter circuit, that is in the first voltage domain and that is configured and arranged to transmit communication signals; a receiver circuit, that is in the second voltage domain, and that has an input that is configured and arranged to receive the communication signals in the second voltage domain; an isolation circuit configured and arranged to provide capacitive isolation for the communication signals between the first and the second voltage domain, the isolation circuit including a first capacitive structure located on the first substrate and including, a first capacitive plate having a first horizontal size and configured and arranged to receive the communication signals from the transmitter circuit and in the first voltage domain, and a second capacitive plate having a second horizontal size, the second capacitive plate being parallel to and separated from the first capacitive plate by a first dielectric layer, the second capacitive plate being configured and arranged as a first floating node of the isolation circuit, the second horizontal size differing from the horizontal size of the first capacitive plate such that a breakdown voltage between the first and second capacitive plates is increased relative to a breakdown voltage for a common horizontal size for the first and second capacitive plates; a second capacitive structure located on the second substrate and including, a third capacitive plate that is configured and arranged as a second floating node and having a third horizontal size, and a fourth capacitive plate having a fourth horizontal size, the fourth capacitive plate being parallel to and separated from the third capacitive plate by a second dielectric layer, the fourth capacitive plate configured and arranged to provide the communication signals to the input of the receiver in the second voltage domain, the fourth horizontal size differing from the third horizontal size such that breakdown voltage between the third and fourth capacitive plates is increased relative to a common horizontal size for the third and fourth capacitive plates; and an electrical connection between the second and third capacitive plates.