Analog Devices Inc. EVAL-AD7785EBZ

Overview

EVAL-AD7785EBZ from Analog Devices is a USB-powered evaluation board designed exclusively for the AD7785 20-bit, low-power sigma-delta ADC with three differential input channels, on-board 3.3 V regulator (ADP3303ARZ-3.3), and integrated temperature demonstration circuit using a 1 kΩ thermistor and 5 kΩ precision reference resistor.

For engineers reviewing the EVAL-AD7785EBZ datasheet, EVAL-AD7785EBZ pinout, EVAL-AD7785EBZ application, or EVAL-AD7785EBZ equivalent, this board enables rapid functional validation of the AD7785's ratiometric temperature sensing, low-noise DC measurement at 16.7 Hz (85 nV rms noise), and programmable gain (1–128) without external clocking or layout design effort.

Technical Context

The EVAL-AD7785EBZ implements a complete analog front-end test environment for the AD7785, featuring SMB connectors for AIN1±/REFIN1±, configurable link settings (LK1–LK7) to select internal reference, excitation current routing, and AVDD source (USB 5 V, ADP3303 3.3 V, or external supply via J3), and a Cypress CY7C68013A-56LFXC USB-to-SPI bridge controller.

It supports simultaneous 50 Hz/60 Hz rejection at 16.7 Hz update rate, uses an on-board 24 MHz crystal (X24M000000S244) for timing, and includes LabVIEW-based PC software for register-level configuration, real-time waveform/histogram display, and temperature conversion via look-up table - all without requiring external instrumentation.

Key Specifications

Availability

EVAL-AD7785EBZ is available at Aetrix Electronics and suitable for precision sensor evaluation, industrial DC measurement prototyping, and medical-grade temperature sensing development requiring stable component supply and full technical documentation support.

Supply support for EVAL-AD7785EBZ 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 Norwood, MA, with deep expertise in precision data acquisition and sensor interface solutions.

The EVAL-AD7785EBZ belongs to Analog Devices' precision ADC evaluation platform family, engineered specifically to accelerate validation of low-frequency, high-resolution measurement systems in industrial, medical, and environmental monitoring applications.

FAQ

What is the primary function of the EVAL-AD7785EBZ?

The EVAL-AD7785EBZ is a dedicated evaluation board for the AD7785 20-bit sigma-delta ADC. It provides a ready-to-use hardware and software environment to configure, test, and validate the AD7785's performance-including its three differential input channels, programmable gain (1–128), internal reference, and on-chip current sources-without custom PCB design. The EVAL-AD7785EBZ includes USB interface, SMB analog connectors, and LabVIEW-based control software.

Does the EVAL-AD7785EBZ require an external power supply?

No, the EVAL-AD7785EBZ is fully powered via the USB Mini-B connector (J1) delivering 5 V. An on-board ADP3303ARZ-3.3 voltage regulator generates clean 3.3 V for the AD7785 and USB interface. External power (3 V or 5 V) may optionally be applied via terminal block J3, and link LK7 selects the AVDD source (Position A = external, B = ADP3303, C = USB 5 V).

How does the temperature demonstration circuit work on the EVAL-AD7785EBZ?

The EVAL-AD7785EBZ integrates a ratiometric temperature sensing circuit: when links LK2–LK6 are installed, the AD7785's on-chip 210 μA current source excites a 1 kΩ thermistor (B57620C102J62) connected across AIN2(+) and AIN2(−), while a 5 kΩ precision resistor (RN73C2A4K99BTG) sets the reference voltage. The EVAL-AD7785EBZ software reads conversions and maps them to temperature using an internal look-up table.

Can the EVAL-AD7785EBZ operate with an external reference voltage?

Yes, the EVAL-AD7785EBZ supports external reference operation via SMB connectors REFIN1+ and REFIN1−. When configured in software (Registers window → Reference = External), the board accepts an external reference voltage applied to those terminals. The default startup mode uses the AD7785's internal reference, but the EVAL-AD7785EBZ hardware provides full flexibility for both internal and external reference configurations.

Is the EVAL-AD7785EBZ compatible with modern Windows operating systems?

Yes, the EVAL-AD7785EBZ software is compatible with Windows® platforms and installs via setup.exe from the included CD. The USB interface is recognized as "AD779x Evaluation Board" by Windows, and driver installation proceeds automatically after software setup. No additional hardware drivers or firmware updates are required to operate the EVAL-AD7785EBZ on supported Windows versions.