AD7718BRZ-REEL7

Overview

The AD7718BRZ-REEL7 is a complete analog front-end featuring a 24-bit Sigma-Delta ADC with an integrated programmable gain amplifier. It supports 4/5 fully-differential or 8/10 pseudo-differential input channels and operates from single 3 V or 5 V supplies. The device achieves a maximum output update rate of 1.365 kS/s with simultaneous 50 Hz and 60 Hz rejection capabilities. Key electrical parameters include a typical power dissipation of 3.84 mW at 3 V, an integral nonlinearity of ±10 ppm of FSR, and a gain error of ±0.003% FSR. It utilizes a 32 kHz crystal oscillator and communicates via a 3-Wire serial interface.

Feature Summary

• Factory-calibrated architecture ensuring high accuracy without external calibration requirements.
• Configurable input modes supporting both fully-differential and pseudo-differential signal connections.
• Integrated programmable gain amplifier allowing direct transducer signal conversion.
• Software-selectable output data rates optimized for either analog performance or channel throughput.

Applications

• Industrial process control systems
• High-resolution instrumentation
• Pressure transducers
• Portable battery-powered instrumentation
• Smart transmitters

Procurement Notes

Verify the component status as End-of-Life (EOL) before procurement planning. Confirm that the SOIC-28 package variant matches the design requirements. Ensure supply chain availability through authorized distributors given the discontinuation status. Validate RoHS compliance documentation for final assembly integration.

Selection Notes

Select this component for applications requiring high resolution and low power consumption in multiplexed data acquisition systems. Compare against the AD7708 if 16-bit resolution suffices for the specific application needs. Consider the CHOP mode settings to balance between noise performance and channel throughput based on system latency requirements.

Part Context

This part belongs to the AD7708/AD7718 family of low voltage, low power analog-to-digital converters. It shares pin compatibility with the 16-bit AD7708, facilitating easy upgrades from 16-bit to 24-bit resolution without hardware modifications. The BRZ suffix indicates a lead-free, halogen-free SOIC-28 package compliant with environmental standards.

Replacement Considerations

The AD7708BRZ is a pin-compatible alternative offering 16-bit resolution. For higher performance requirements, consider newer Analog Devices sigma-delta ADCs, though pin compatibility may vary. Verify functional equivalence regarding interface protocols and power specifications when substituting.

FAQ

Can the AD7718 operate with both 3 V and 5 V supplies simultaneously?

Yes, the AVDD and DVDD pins can be operated independently from each other, allowing different voltage levels for analog and digital domains within their specified ranges.

What is the purpose of the CHOP function in this device?

The CHOP function allows optimization for either analog performance (CHOP = 0) or channel throughput (CHOP = 1), affecting the output update rate and noise characteristics.

How does the VREF Select feature benefit measurements?

VREF Select allows the device to support both absolute and ratiometric measurement capabilities by configuring the reference inputs appropriately.