Texas Instruments ADS8681EVM-PDK

Overview

ADS8681EVM-PDK from Texas Instruments is an evaluation platform for the ADS8681 16-bit, 1-Msps SAR ADC, featuring constant resistive input impedance and multiSPI™ digital interface. It includes the ADS8681EVM board, Precision Host Interface (PHI) controller board, A-to-micro-B USB cable, and Windows-compatible GUI software for data capture, spectral analysis, histogram analysis, and linearity evaluation.

For engineers reviewing the ADS8681EVM-PDK datasheet, ADS8681EVM-PDK setup, ADS8681EVM-PDK GUI operation, or ADS8681EVM-PDK hardware configuration, this kit delivers full-system evaluation capability with USB-powered operation, jumper-selectable input ranges (±0.625×Vref to ±3×Vref), on-board 4.096-V REF5040 reference, and integrated TPS7A4901 low-noise LDO for analog supply regulation.

Technical Context

The ADS8681EVM-PDK implements a two-board architecture: the ADS8681EVM hosts the target ADC, precision reference (REF5040), ultra-low-noise 5-V analog supply (TPS7A4901), and SMA-based analog input path with TVS overvoltage protection; the PHI controller provides USB 2.0 host interface, SPI/multiSPI communication at 1.8-V logic level, EEPROM-based initialization, and power delivery.

Digital communication uses standard and multiSPI modes (single/dual-SDO, source-synchronous/system-synchronous), configured via GUI-driven register map access. Analog evaluation supports bipolar/unipolar input ranges, on-board 100-mV/4-V test signals, external reference selection via J3 jumper, and configurable low-pass filtering using C1 (330 pF) and selectable resistors.

Key Specifications

Availability

ADS8681EVM-PDK is available at Aetrix Electronics and suitable for high-precision data acquisition system validation, industrial sensor interface prototyping, and medical-grade ADC performance benchmarking requiring stable component supply and full technical support.

Supply support for ADS8681EVM-PDK 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

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, specializing in analog, embedded processing, and high-performance data converter technologies.

The ADS8681EVM-PDK belongs to TI's precision data acquisition evaluation platform family, designed to accelerate development of high-fidelity measurement systems in industrial automation, test & measurement, and medical instrumentation.

FAQ

What is the ADS8681EVM-PDK used for?

The ADS8681EVM-PDK is a complete evaluation system for the ADS8681 16-bit, 1-Msps SAR ADC. It enables engineers to validate dynamic performance metrics-including SNR, THD, SFDR, SINAD, ENOB, DNL, and INL-using its integrated PHI controller, USB interface, and Windows GUI with spectral, histogram, and time-domain analysis tools. The ADS8681EVM-PDK supports both bipolar and unipolar input configurations and allows direct register-level control of the ADS8681 device.

Does the ADS8681EVM-PDK require an external power supply?

No, the ADS8681EVM-PDK is fully USB-powered via the included A-to-micro-B cable and the PHI controller board. The PHI derives 5.5 V for the TPS7A4901 LDO (generating clean 5-V AVDD) and 3.3 V for digital circuits directly from the USB port. An external 5-V supply can be used optionally by installing a jumper on J4 pins 2–3, but it is not required for standard operation of the ADS8681EVM-PDK.

How is the reference voltage selected on the ADS8681EVM-PDK?

The ADS8681EVM-PDK supports both internal and external reference selection. By default, the ADS8681 uses its internal 4.096-V reference; J3 must remain open during power-up. To use the external REF5040 (U2), bit 6 of the RANGE_SEL_REG register must first be set to disable the internal reference, then J3 is closed. This configuration is managed through the Register Map Configuration tool in the ADS8681EVM-PDK GUI software.

What input signal options does the ADS8681EVM-PDK provide?

The ADS8681EVM-PDK offers three analog input paths: (1) external signal via SMA connector J1; (2) 100-mV buffered DC source (J5.Pin6); and (3) 4-V buffered DC source (J5.Pin4). Jumper settings on J5 determine active input-open all jumpers for J1, close J5.Pin5–J5.Pin6 for VTL (100 mV), or close J5.Pin3–J5.Pin4 for VTH (4 V). All configurations maintain the ADS8681's constant resistive input impedance without external buffering.

Which software tools are included with the ADS8681EVM-PDK?

The ADS8681EVM-PDK includes a Windows GUI with five core analysis modules: Time Domain Display (real-time code/voltage waveform), Histogram Analysis (effective resolution, sigma, code spread), Spectral Analysis (FFT-based SNR/THD/SFDR/SINAD/ENOB using 7-term Blackman-Harris window), Linearity Analysis (DNL and INL plots), and Register Map Configuration (bit-level register read/write). All tools operate over USB via the PHI controller and support iterative parameter tuning for optimal ADS8681EVM-PDK evaluation.