Catalog
Isolated Sigma-Delta Modulator
Key Features
• 20 MHz maximum external clock rate
• Second-order modulator
• 16 bits no missing codes
• ±2 LSB INL typical at 16 bits
• 3.5 μV/°C maximum offset drift
• On-board digital isolator
• On-board reference
• Low power operation: 20 mA maximum at 5.25 V
• −40°C to +105°C operating range
• 16-lead SOIC package
• Safety and regulatory approvals
• See Data Sheet for Addtional Features
Description
AI
The AD7401 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 Analog Devices, Inc.,iCoupler®technology. The AD7401 operates from a 5 V power supply and accepts a differential input signal of ±200 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 up to 20 MHz. The original information can be reconstructed with an appropriate digital filter. The serial input/output can use a 5 V or a 3 V supply (VDD2).The serial interface is digitally isolated. High speed CMOS, combined with monolithic air core transformer 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 AD7401 is offered in a 16-lead SOIC and has an operating temperature range of −40°C to +105°C.An internal clock version, AD7400, is also available.APPLICATIONSAC motor controlsData acquisition systemsA/D + opto-isolator replacements
