The AD7401A is a second-order, sigma-delta (Σ-Δ) modulator that converts an analog input signal into a high speed, 1-bit data stream with on-chip digital isolation based on the Analog Devices, Inc.,iCoupler®technology. The AD7401A operates from a 5 V power supply and accepts a pseudo-differential input signal of ±250 mV (±320 mV 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 of up to 20 MHz. The original information can be reconstructed with an appropriate digital filter. The serial I/O can use a 5 V or a 3.3 V supply (VDD2).The serial interface is digitally isolated. High speed CMOS, combined with Analog Devices, Inc.,iCoupler®technology, means the on-chip isolation provides outstanding performance characteristics, superior to alternatives such as optocoupler devices. The device contains an on-chip reference. The AD7401A is offered in a 16-lead SOIC and has an operating temperature range of −40°C to +125°C.ApplicationsAC motor controlsShunt current monitoringData acquisition systemsAnalog-to-digital and opto-isolator replacements