Texas Instruments ADC121S625EVAL/NOPB

Overview

ADC121S625EVAL/NOPB from Texas Instruments (formerly National Semiconductor) is an evaluation board designed to accelerate prototyping and performance validation of the ADC121S625 - a 12-bit, differential-input, serial-output SAR analog-to-digital converter operating at 50–200 kSPS with micro-power consumption (2.7 mW at 200 kSPS). It supports both standalone logic analyzer-based testing and computer-controlled acquisition via WaveVision4 software and the WV4 Data Capture Board.

For engineers reviewing the ADC121S625EVAL/NOPB datasheet, ADC121S625EVAL/NOPB pinout, ADC121S625EVAL/NOPB application, or ADC121S625EVAL/NOPB equivalent, this board enables rapid functional verification, dynamic parameter measurement (SNR, SINAD, THD, SFDR, ENOB), clock source selection (on-board 4 MHz oscillator or external TTL clock up to 4 MHz), flexible reference configuration (2.5 V shunt or VA), and differential AC/DC analog input evaluation under real-world signal conditions.

Technical Context

The ADC121S625EVAL/NOPB implements a complete test environment for the ADC121S625 IC (U1, MSOP-8), including configurable clock routing (JP5 selects between Y2 oscillator or J6 BNC input), dual analog input paths (J2 for ground-centered AC signals, J3 for DC-biased differential inputs), and selectable reference voltage (JP1 chooses LM4040 2.5 V shunt or VA).

It provides hardware-level signal conditioning via R4 termination (user-configurable for 50 Ω sources), bias control (JP2 enables VREF-based input biasing for J2), and power isolation (separate 5P0V_REMOTE and 3P3V rails), enabling accurate characterization of the ADC's 0 V to 2×VREF input range, 800 kHz–4 MHz clock tolerance, and 90 dB THD minimum input signal requirement.

Key Specifications

Availability

ADC121S625EVAL/NOPB is available at Aetrix Electronics and suitable for high-precision data acquisition system development, sensor signal chain validation, and mixed-signal IC qualification requiring stable component supply, traceable sourcing, and long-term evaluation platform continuity.

Supply support for ADC121S625EVAL/NOPB 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 acquired National Semiconductor in 2011 and maintains legacy evaluation platforms like ADC121S625EVAL/NOPB under its precision data converter portfolio.

This evaluation board belongs to TI's legacy analog evaluation kit family, specifically engineered to de-risk design-in of low-power, high-resolution SAR ADCs in instrumentation, industrial sensing, and portable measurement applications.

FAQ

What is the primary function of the ADC121S625EVAL/NOPB?

The ADC121S625EVAL/NOPB is a dedicated evaluation platform for the ADC121S625 12-bit SAR analog-to-digital converter. It enables engineers to validate performance parameters-including SNR, SINAD, THD, SFDR, and ENOB-under controlled conditions using either standalone test equipment or computer-based WaveVision4 software. The ADC121S625EVAL/NOPB does not perform conversion itself but hosts and exercises the ADC121S625 IC (U1) with configurable clock, reference, and input circuitry.

Does the ADC121S625EVAL/NOPB require the WaveVision4 Data Capture Board to operate?

No - the ADC121S625EVAL/NOPB supports two independent operating modes. In Stand-Alone Mode, it can be used with a logic analyzer or oscilloscope to monitor CSB, SCLK, and DOUT signals directly at J4. In Computer Mode, it connects to the WV4 Data Capture Board via ribbon cable (WV4ADCIFCABLE) for automated data capture and FFT analysis. Both modes are fully supported by the ADC121S625EVAL/NOPB hardware and documentation.

What clock sources are supported by the ADC121S625EVAL/NOPB?

The ADC121S625EVAL/NOPB supports two clock sources: an on-board 4.0 MHz crystal oscillator (Y2) or an external TTL-level clock applied to BNC connector J6. JP5 jumper selects between them - pins 1&2 enable Y2, pins 2&3 route J6. For reliable ADC121S625 operation, only one source must be active; mixing sources introduces noise and violates timing integrity.

How is the reference voltage configured on the ADC121S625EVAL/NOPB?

The ADC121S625EVAL/NOPB offers three VREF options via JP1: shorting pins 2&3 selects the onboard LM4040DIM3-2.5 (2.5 V shunt reference); shorting pins 1&2 selects VA (the ADC's analog supply); removing the jumper allows direct injection of an external reference at pin 2. This flexibility lets users correlate ADC121S625 performance against different reference stability and noise profiles.

Can the ADC121S625EVAL/NOPB evaluate both AC and DC differential input signals?

Yes - the ADC121S625EVAL/NOPB provides two dedicated differential input paths: J2 is optimized for ground-centered AC signals (with optional R4 termination and JP2 biasing to VREF), while J3 accepts pre-biased DC or dynamically biased differential signals without additional biasing. When using J3, JP2 jumpers must be removed to avoid conflict. Both paths connect directly to the ADC121S625's +IN and –IN pins, preserving full differential mode functionality.