Analog Devices Inc. AD7401 Isolated Sigma-Delta Modulators are based on ADI's iCoupler® technology and convert an analog input signal into a high speed, 1-bit data stream with on-chip digital isolation. Analog Devices AD7401 is a second-order, sigma-delta (Σ-Δ) modulator that operates from a 5V power supply and accepts a differential input signal of ±200mV (±320mV full scale). The analog input is continuously sampled by the analog modulator, eliminating the need for external sample-and-hold circuitry. The input information is contained in the output stream as a density of ones with a data rate up to 20MHz. The original information can be reconstructed with an appropriate digital filter. The serial input/output can use a 5V or a 3V supply (VDD2).