The AMC0381D-Q1 uses an on-off keying (OOK) modulation scheme, as shown in Figure 6-1, to transmit the modulator output bitstream across the SiO₂-based isolation barrier. The transmit driver (TX), as illustrated in the Functional Block Diagram, transmits an internally generated, high-frequency carrier across the isolation barrier to represent a digital one. However, TX does not send a signal to represent a digital zero. The nominal frequency of the carrier used inside the AMC0381D-Q1 is 480MHz.

The receiver (RX) on the other side of the isolation barrier recovers and demodulates the signal and provides the input to the fourth-order analog filter. The AMC0381D-Q1 transmission channel is optimized to achieve the highest level of common-mode transient immunity (CMTI) and the lowest level of radiated emissions. The high-frequency carrier and RX/TX buffer switching cause these emissions.

Figure 6-1 OOK-Based Modulation Scheme