AD7986BCPZ-RL7

Overview

The AD7986BCPZ-RL7 is an 18-bit, 2 MSPS PulSAR analog-to-digital converter in a 20-lead LFCSP package. It features a true differential analog input range of ±VREF or 0 V to VREF with VREF up to 5.0 V. The device includes a 4.096 V internal reference with a typical drift of 10 ppm/°C and operates on AVDD/DVDD at 2.5 V and BVDD at 5.0 V. Power dissipation is 15 mW at 2 MSPS with an external reference and 29 mW with the internal reference. Key accuracy metrics include an INL of ±2.5 LSB maximum and an SNR of 97.0 dB with an external reference.

Feature Summary

• Proprietary serial interface compatible with SPI, QSPI, MICROWIRE, and DSP standards.
• Turbo mode enables maximum throughput of 2 MSPS without power-down between conversions.
• Normal mode reduces power consumption by powering down between conversions at lower throughput.
• Supports daisy-chaining multiple ADCs on a single bus with an optional busy indicator.

Applications

• Battery-powered equipment
• Data acquisition systems
• Medical instruments
• Seismic data acquisition systems

Procurement Notes

Verify the specific ordering suffix RL7 indicates reel packaging when sourcing components. Confirm that the LFCSP-20 package matches the target PCB footprint and thermal requirements. Ensure the voltage levels for AVDD, DVDD, and VIO align with the system design specifications before integration.

Selection Notes

Select this component for applications requiring high resolution and moderate speed. Consider the internal reference if board space is limited, noting the higher power consumption compared to using an external reference. Evaluate the need for turbo versus normal mode based on power constraints and throughput requirements.

Part Context

This part belongs to the AD7986 series of 18-bit PulSAR ADCs from Analog Devices. It shares architectural similarities with the AD7985 (16-bit) and AD7944 (14-bit). The family utilizes a successive approximation register architecture optimized for low power and high accuracy in compact packages.

Replacement Considerations

The AD7985 is a pin-compatible 16-bit alternative within the same family. Verify functional requirements against the AD7985 datasheet to ensure resolution differences do not impact system performance.

FAQ

What is the difference between Turbo and Normal modes?

Turbo mode (TURBO = high) allows a maximum throughput of 2 MSPS without powering down between conversions. Normal mode (TURBO = low) reduces power consumption by powering down between conversions, resulting in a maximum throughput of 1.5 MSPS.

How is the internal reference controlled?

The internal reference is enabled when the PDREF pin is low. When PDREF is high, the internal reference is powered down, allowing an external reference voltage up to 5.0 V to be applied to the REF pin.

What is the digital interface compatibility?

The AD7986 features a versatile serial interface port compatible with SPI, QSPI, MICROWIRE, and DSP standards. It supports 1.8 V, 2.5 V, and 2.7 V logic levels via the VIO supply.