AD7403 Sigma-Delta Modulator

The AD7403 is a high-performance, second-order, Σ-Δ modulator that converts an analog input signal into a high-speed, single-bit data stream, with on-chip digital isolation based on Analog Devices, Inc. iCoupler^® technology. The AD7403 operates from a 5 V (V_DD1) power supply and accepts a differential input signal of ±250 mV (±320 mV full-scale). The differential input is ideally suited to shunt voltage monitoring in high-voltage applications where galvanic isolation is required.

The analog input is continuously sampled by a high-performance analog modulator, and converted to a ones density digital output stream with a data rate of up to 20 MHz. The original information can be reconstructed with an appropriate digital filter to achieve 88 dB signal-to-noise ratio (SNR) at 78.1 kSPS. The serial input/output can use a 5 V or a 3 V supply (V_DD2).

The serial interface is digitally isolated. High-speed complementary metal oxide semiconductor (CMOS) technology, combined with monolithic transformer technology, means the on-chip isolation provides outstanding performance characteristics, superior to alternatives such as optocoupler devices. The AD7403 device is offered in a 16-lead, wide-body SOIC package and has an operating temperature range of −40°C to +125°C.

Applications