Analog Devices Inc. EVAL-AD7794EBZ

Overview

EVAL-AD7794EBZ from Analog Devices is a USB-powered evaluation board designed to characterize and validate the AD7794 24-bit, low-power, sigma-delta ADC with six differential analog inputs, 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-AD7794EBZ datasheet, EVAL-AD7794EBZ pinout, EVAL-AD7794EBZ application, or EVAL-AD7794EBZ equivalent, this board enables rapid configuration of gain (1–128), update rate (4.17–470 Hz), ratiometric temperature measurement, internal/external reference selection, and low-side power switch testing via LabVIEW™-based PC software.

Technical Context

The EVAL-AD7794EBZ implements a complete hardware interface for the AD7794, including SMB connectors for AIN1(±), REFIN1(±), configurable link settings (LK1–LK8) for reference selection, thermistor routing, bias voltage, and AVDD sourcing (USB 5 V, external supply, or ADP3303 3.3 V), and a Cypress CY7C68013A-56LFXC USB-to-SPI bridge controller.

It supports full register-level access to the AD7794's configuration, mode, and I/O registers; enables real-time noise analysis at 16.7 Hz (87 nV rms with gain = 64); and provides dedicated Temp Demo mode that configures excitation current (210 μA), channel AIN4(±), gain = 1, and ratiometric reference for ambient temperature conversion using an on-board lookup table.

Key Specifications

Availability

EVAL-AD7794EBZ is available at Aetrix Electronics and suitable for precision sensor interface validation, industrial temperature monitoring prototyping, and low-frequency data acquisition system development requiring stable component supply and traceable evaluation hardware.

Supply support for EVAL-AD7794EBZ 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, serving industrial, instrumentation, medical, and communications markets since 1965.

EVAL-AD7794EBZ belongs to Analog Devices' precision ADC evaluation platform family, engineered specifically to accelerate design-in of low-noise, low-power, multi-channel sigma-delta converters for high-resolution sensor signal conditioning and metrology applications.

FAQ

What is the primary function of the EVAL-AD7794EBZ?

The EVAL-AD7794EBZ is a fully featured evaluation board for the AD7794 24-bit sigma-delta ADC. It enables engineers to configure, test, and validate the device's performance-including gain (1–128), update rate (4.17–470 Hz), ratiometric temperature measurement, and low-side power switch operation-using included Windows-based LabVIEW™ software and USB connectivity. The EVAL-AD7794EBZ does not replace production hardware but serves strictly as a characterization and development tool.

Does the EVAL-AD7794EBZ require an external power supply?

No, the EVAL-AD7794EBZ is powered directly via the USB Mini-B connector (J1), delivering 5 V to the board. An onboard ADP3303ARZ-3.3 regulator generates a clean 3.3 V supply for the AD7794's AVDD when LK8 is set to Position B. External 3 V or 5 V power can be applied via terminal block J3 only if LK8 is set to Position A - making external power optional, not required. The EVAL-AD7794EBZ operates fully standalone from USB power.

How is temperature measurement implemented on the EVAL-AD7794EBZ?

The EVAL-AD7794EBZ implements ratiometric temperature measurement using an on-board 1 kΩ thermistor (R1) and 5 kΩ precision resistor (R2). When links LK2–LK6 are installed, the AD7794's internal 210 μA current source excites the thermistor, and the resulting voltage across AIN4(±) is measured against the resistor-generated reference. The included Temp Demo software performs real-time conversion using a lookup table - all without external components. This functionality is exclusive to the EVAL-AD7794EBZ hardware configuration.

Can the EVAL-AD7794EBZ be used with other ADCs besides the AD7794?

No, the EVAL-AD7794EBZ is specifically designed for the AD7794BRUZ and is not compatible with other ADCs. Its schematic, layout, link configuration (LK1–LK8), SMB connector assignments, and firmware are optimized exclusively for the AD7794's pinout, register map, power sequencing, and feature set - including its embedded reference, programmable current sources, and low-side power switch. Using it with any other device is neither supported nor electrically safe.

What software is required to operate the EVAL-AD7794EBZ?

The EVAL-AD7794EBZ requires the official Analog Devices AD7794 evaluation software, distributed on CD with the board and available for download from analog.com. This Windows-based LabVIEW™ application provides full register access, real-time sampling, noise analysis, waveform/histogram display, and temperature demo functionality. Installation must precede physical connection to ensure proper USB enumeration as "AD779x Evaluation Board" - the EVAL-AD7794EBZ does not function with generic USB or SPI utilities.