Analog Devices Inc. EVAL-AD7708EBZ

Overview

EVAL-AD7708EBZ from Analog Devices is a fully featured evaluation board for the AD7708 16-bit sigma-delta ADC, enabling rapid prototyping and characterization of low-frequency analog front-end designs. It supports up to 10 analog input channels (AIN1–AIN8, AINCOM, AIN9/AIN10), features dual on-board AD780 2.5 V precision references, and integrates a 32.768 kHz crystal oscillator for stable master clocking in sensor measurement applications.

For engineers reviewing the EVAL-AD7708EBZ datasheet, EVAL-AD7708EBZ pinout, EVAL-AD7708EBZ application, or EVAL-AD7708EBZ equivalent, this board provides direct PC interface via parallel port (J1) or custom system interface via 9-pin D-sub (J4), configurable analog input linking (LK1–LK15), software-controlled register access, and real-time noise analysis - all critical for validating high-accuracy, low-power transducer signal chains.

Technical Context

The EVAL-AD7708EBZ implements a complete hardware test environment for the AD7708, including buffered serial interface signals (SCLK, DIN, DOUT, CS, RDY, RESET, SYNC), isolated analog and digital power domains (AVDD/AGND and DVDD/DGND), and flexible reference routing via jumper-selectable links (LK10–LK13). All digital I/O lines are buffered using 74HC4050N, 74C08SMD, and 74ACT244 ICs to ensure signal integrity during host communication.

It supports both internal (32.768 kHz crystal at XTAL1) and external master clock sources (via SKT16), offers 18 SMB sockets for analog inputs, reference injection, I/O pin access (P1/P2), and clock input, and includes a push-button hardware reset (SW1) that asserts the active-low RESET pin of the AD7708. Link configurations (LK1–LK9) enable direct connection or isolation of each analog input channel to its corresponding socket.

Key Specifications

Availability

EVAL-AD7708EBZ is available at Aetrix Electronics and suitable for industrial sensor interface validation, precision weigh-scale development, and medical instrumentation prototyping requiring stable component supply and full functional verification of the AD7708 ADC.

Supply support for EVAL-AD7708EBZ 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-AD7708EBZ belongs to Analog Devices' precision data acquisition evaluation platform family, designed specifically to accelerate development of low-frequency, high-resolution measurement systems using their sigma-delta ADC portfolio.

FAQ

What is the primary function of the EVAL-AD7708EBZ?

The EVAL-AD7708EBZ is an evaluation board built to fully exercise and validate the AD7708 16-bit sigma-delta ADC. It provides hardware infrastructure-including precision references, buffered serial interface, configurable analog inputs, and PC software-to evaluate performance, configure registers, run calibrations, and analyze noise in real-world low-frequency measurement scenarios without custom PCB design.

Does the EVAL-AD7708EBZ require external power supplies?

Yes, the EVAL-AD7708EBZ requires two independent power supplies: +5 V applied between AVDD and AGND for analog circuitry and reference generation, and a separate DVDD supply (typically +5 V) for digital buffers and logic. DGND and AGND are internally joined only at the AD7708 ground pin, so external system-level grounding must respect this separation to avoid noise coupling.

How does the EVAL-AD7708EBZ interface with a PC?

The EVAL-AD7708EBZ interfaces with a Windows PC via its 36-pin Centronics connector (J1), using a standard parallel printer cable. The included software communicates directly through LPT1, LPT2, or PRN ports to control the AD7708 registers, acquire samples, perform noise analysis, and visualize data - no additional drivers or USB adapters are required for basic operation.

Can the EVAL-AD7708EBZ support external reference voltages?

Yes, the EVAL-AD7708EBZ supports external references via dedicated SMB sockets SKT10–SKT13 and jumpers LK10–LK13. When configured in position "B", LK10 connects SKT10 to REFIN2(+)/AIN9, LK11 connects SKT11 to REFIN2(−)/AIN10, and similarly for REFIN1(+) and REFIN1(−) on SKT12/SKT13 - enabling user-defined reference topologies while retaining full AD7708 functionality.

What software features are included with the EVAL-AD7708EBZ?

The EVAL-AD7708EBZ ships with Windows-based software supporting register-level programming (Mode, Filter, ADC Control, Calibration, I/O, Status), multi-channel sampling with configurable update rates, real-time noise analysis (RMS, peak-to-peak, histogram, graph), and data export to Excel or Mathcad. It also enables hardware/software reset, internal/full-scale calibration, and pseudo-differential channel testing - all without modifying firmware or hardware.