Abstract: A digital isolator provided includes a pair of transceiver circuits and a control circuit. Each transceiver circuit includes a transmitter circuit, a receiver circuit, and a DC isolation circuit. When the control circuit controls one of the pair of transceiver circuits to operate in a transmitting mode and the other of the pair of transceiver circuits to operate in a receiving mode, the transmitting circuit of the transceiver circuit operating in the transmitting mode receives a square wave signal to generate a pair of differential square wave signals, the connected DC isolation circuits receive the pair of differential square wave signals to generate a pair of differential coupling signals, and the transceiver circuit operating in the receiving mode uses the pair of differential coupling signals to output the square wave signal through the design of a pair of feedback voltage divider circuits and a differential comparison circuit included therein.