A data communication circuit comprising: a differential transmitter configured to transmit a first digital bit stream via a first unidirectional isolation channel, the first unidirectional isolation channel being a first differential channel; a differential receiver configured to receive a second digital bit stream via a second unidirectional isolation channel, the second unidirectional isolation channel being a second differential channel, and the first unidirectional isolation channel and the second unidirectional isolation channel being defined on a common dielectric substrate and being galvanically isolated; and a crosstalk suppression circuit configured to provide at least one negative feedback signal to suppress crosstalk between the differential transmitter and the differential receiver due to parasitic capacitive coupling between the first unidirectional isolation channel and the second unidirectional isolation channel in the common dielectric substrate, wherein: the crosstalk suppression circuit includes a variable capacitance circuit, the data communication circuit being configured to adjust a capacitance of the variable capacitance circuit based on the parasitic capacitive coupling between the first unidirectional isolation channel and the second unidirectional isolation channel; and the at least one negative feedback signal includes: a first negative feedback signal applied between a positive output terminal of the differential transmitter and a negative input terminal of the differential receiver by a first capacitor of the variable capacitance circuit; and a second negative feedback signal applied between a negative output terminal of the differential transmitter and a positive input terminal of the differential receiver by a second capacitor of the variable capacitance circuit. a differential transmitter configured to transmit a first digital bit stream via a first unidirectional isolation channel, the first unidirectional isolation channel being a first differential channel; a differential receiver configured to receive a second digital bit stream via a second unidirectional isolation channel, the second unidirectional isolation channel being a second differential channel, and the first unidirectional isolation channel and the second unidirectional isolation channel being defined on a common dielectric substrate and being galvanically isolated; and a crosstalk suppression circuit configured to provide at least one negative feedback signal to suppress crosstalk between the differential transmitter and the differential receiver due to parasitic capacitive coupling between the first unidirectional isolation channel and the second unidirectional isolation channel in the common dielectric substrate, wherein: the crosstalk suppression circuit includes a variable capacitance circuit, the data communication circuit being configured to adjust a capacitance of the variable capacitance circuit based on the parasitic capacitive coupling between the first unidirectional isolation channel and the second unidirectional isolation channel; and the at least one negative feedback signal includes: a first negative feedback signal applied between a positive output terminal of the differential transmitter and a negative input terminal of the differential receiver by a first capacitor of the variable capacitance circuit; and a second negative feedback signal applied between a negative output terminal of the differential transmitter and a positive input terminal of the differential receiver by a second capacitor of the variable capacitance circuit. the crosstalk suppression circuit includes a variable capacitance circuit, the data communication circuit being configured to adjust a capacitance of the variable capacitance circuit based on the parasitic capacitive coupling between the first unidirectional isolation channel and the second unidirectional isolation channel; and the at least one negative feedback signal includes: a first negative feedback signal applied between a positive output terminal of the differential transmitter and a negative input terminal of the differential receiver by a first capacitor of the variable capacitance circuit; and a second negative feedback signal applied between a negative output terminal of the differential transmitter and a positive input terminal of the differential receiver by a second capacitor of the variable capacitance circuit. a first negative feedback signal applied between a positive output terminal of the differential transmitter and a negative input terminal of the differential receiver by a first capacitor of the variable capacitance circuit; and a second negative feedback signal applied between a negative output terminal of the differential transmitter and a positive input terminal of the differential receiver by a second capacitor of the variable capacitance circuit.