The isolation inside the UCC5390-Q1 is implemented with high-voltage SiO₂-based capacitors. The signal across the isolation has an on-off keying (OOK) modulation scheme to transmit the digital data across a silicon dioxide based isolation barrier (see Figure 7-2). The transmitter sends a high-frequency carrier across the barrier to represent one digital state and sends no signal to represent the other digital state. The receiver demodulates the signal after advanced signal conditioning and produces the output through a buffer stage. The UCC5390-Q1 also incorporates advanced circuit techniques to maximize the CMTI performance and minimize the radiated emissions from the high frequency carrier and IO buffer switching. The conceptual block diagram of a digital capacitive isolator, Figure 7-1, shows a functional block diagram of a typical channel. Figure 7-2 shows a conceptual detail of how the OOK scheme works.

Figure 7-1 shows how the input signal passes through the capacitive isolation barrier through modulation (OOK) and signal conditioning.