SLUAB06 January 2025 AMC131M02 , AMC3330 , ISO7731
The AMC3330 is a fully-differential precision isolated amplifier with high-input impedance, and an integrated DC/DC converter that allows the device to be supplied from a single 3.3V or 5V voltage supply source from the low voltage side. The input stage of the device drives a 2nd-order, delta-sigma (ΔΣ) modulator. The modulator uses an internal voltage reference and clock generator to convert the analog input signal to a digital bit stream. The drivers (termed TX in the Functional Block Diagram) transfer the output of the modulator across the isolation barrier that separates the high-side and low-side voltage domains. The received bit stream and clock are synchronized and processed by a 4th-order analog filter on the low-side and presented as a differential analog output.
The 1.2GΩ differential input impedance of the analog input stage supports low gain-error signal-sensing in high-voltage applications using high-impedance resistor dividers. The signal path is isolated by a double capacitive silicon-dioxide (SiO2) insulation barrier, whereas power isolation uses an on-chip transformer separated by a thin-film polymer as the insulating material.