Analog Devices Inc. EVAL-AD7685SDZ

Overview

EVAL-AD7685SDZ from Analog Devices is an evaluation board designed specifically for the AD7685 - a 16-bit, 250 kSPS PulSAR® successive approximation register (SAR) analog-to-digital converter in a 10-lead MSOP package. It provides full signal chain support including on-board ADR435 5.0 V reference, ADA4841-1 ADC drivers, and dual-rail ±7.5 V/–2.5 V analog power supplies. The board enables high-fidelity dynamic testing (SNR, SINAD, THD, SFDR) of the AD7685 in precision data acquisition systems.

For engineers reviewing the EVAL-AD7685SDZ datasheet, EVAL-AD7685SDZ pinout, EVAL-AD7685SDZ application, or EVAL-AD7685SDZ equivalent, this page delivers verified hardware configuration details, software operation guidance, SDP interface compatibility, analog input conditioning options, and real-world test setup requirements for accurate ADC characterization.

Technical Context

The EVAL-AD7685SDZ implements a modular, low-noise analog front-end with SMA-connected differential or single-ended inputs, unity-gain buffered amplifiers (ADA4841-1), and precision common-mode voltage generation (VCM). It interfaces to the EVAL-SDP-CB1Z system demonstration platform via a 120-pin connector using SPORT protocol over SCK/SDI/SDO/CNV signals.

Power is derived from a 9 V wall adapter or bench supply, generating regulated +7.5 V, –2.5 V, +5 V, +3.3 V, and +2.5 V rails using ADP7102, ADP7104, and ADP2301 regulators. On-board solder links (SL1–SL7, SL10) allow configuration for ADC-specific voltage domains and input topology (differential vs. single-ended).

Key Specifications

Availability

EVAL-AD7685SDZ is available at Aetrix Electronics and suitable for precision sensor interfacing, industrial process monitoring, and medical instrumentation requiring stable component supply and validated ADC evaluation infrastructure.

Supply support for EVAL-AD7685SDZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA.

The EVAL-AD7685SDZ belongs to Analog Devices' PulSAR® evaluation platform family, engineered to accelerate validation of high-resolution SAR ADCs in demanding measurement applications where noise floor, linearity, and timing integrity are critical.

FAQ

What is the primary function of the EVAL-AD7685SDZ?

The EVAL-AD7685SDZ is a dedicated evaluation board for the AD7685 16-bit SAR ADC. It provides complete signal conditioning, precision reference, regulated analog/digital power, and SDP-based digital interface to enable rapid, repeatable performance characterization - including SNR, THD, and INL/DNL - without custom hardware development. The EVAL-AD7685SDZ supports both differential and single-ended input configurations via factory-configurable solder links.

Which ADCs does the EVAL-AD7685SDZ support besides the AD7685?

The EVAL-AD7685SDZ is part of the unified 8-/10-lead PulSAR evaluation platform and supports multiple 10-lead PulSAR ADCs including AD7685, AD7686, AD7687, AD7688, AD7690, AD7691, AD7693, AD7980, AD7982, AD7983, AD7984, AD7988-5, AD7989-5, AD7915, and AD7916. Each variant requires correct jumper (SL10) configuration per Table 3 of UG-340 to match input topology and voltage domain settings.

How does the EVAL-AD7685SDZ connect to a PC for data acquisition?

The EVAL-AD7685SDZ connects to a PC through the EVAL-SDP-CB1Z system demonstration platform, which acts as a USB-to-SPI/SPORT bridge. The SDP board plugs into the PC via a standard USB A-to-Mini-B cable and communicates with the EVAL-AD7685SDZ via its 120-pin edge connector. The included Windows software detects the SDP automatically and configures sampling parameters (SCLK, sample rate) based on the installed ADC's specifications.

What power supplies are generated on the EVAL-AD7685SDZ and how are they used?

The EVAL-AD7685SDZ generates +7.5 V (for analog amplifier positive rail), –2.5 V (for analog amplifier negative rail), +5 V (for SDP interface and reference), +3.3 V (for VDRIVE digital logic), and +2.5 V (for ADC core). These rails are produced from a 9 V input using ADP7102, ADP7104, and ADP2301 regulators. All supplies are locally decoupled, and the board uses a single ground plane to minimize noise coupling between analog and digital sections.

Can the EVAL-AD7685SDZ be used without connecting to a PC or SDP board?

Yes - the EVAL-AD7685SDZ software supports standalone (offline) mode. When launched without hardware, it displays a connectivity warning and allows users to load previously saved .tsv files for post-processing, FFT analysis, histogram plotting, and summary reporting. This enables offline review of captured data, comparison across test conditions, and integration into automated validation workflows without physical hardware connection.