Texas Instruments ADC122S101EVAL

Overview

ADC122S101EVAL from Texas Instruments is an evaluation board for the ADC122S101 - a 12-bit, dual-channel, successive-approximation analog-to-digital converter with SPI-compatible serial interface, operating at 500 ksps to 1 Msps sample rates and supporting 2.7V–5.25V single-supply operation. It enables rapid validation of signal acquisition in portable instrumentation and remote data acquisition systems.

For engineers reviewing the ADC122S101EVAL datasheet, ADC122S101EVAL pinout, ADC122S101EVAL application, or ADC122S101EVAL equivalent, this board provides direct access to the ADC122S101's IN1/IN2 analog inputs, CS/SCLK/DIN/DOUT digital interface, and VA/GND power rails - facilitating timing verification, noise characterization, and channel crosstalk assessment under real-world supply and layout conditions.

Technical Context

The ADC122S101EVAL implements the ADC122S101 IC in an 8-pin VSSOP package with on-board bypass capacitors (1 µF + 0.1 µF), test points for all signals, and jumper-selectable reference configuration (VA as reference). It supports both single-ended input modes (IN1 or IN2) via the ADC122S101's internal multiplexer and control register programming over SPI.

Board-level design follows TI's recommended layout practices: analog and digital grounds are separated but joined at a single point near the ADC ground pin; VA is decoupled within 1 cm of the IC; and SCLK/CS routing minimizes skew to meet tCSU/tCLH timing requirements (−3.5 ns to +4.5 ns at 3V, −0.5 ns to +1.5 ns at 5V).

Key Specifications

Availability

ADC122S101EVAL is available at Aetrix Electronics and suitable for portable instrumentation, remote sensor nodes, and industrial control system development requiring stable component supply, fast evaluation turnaround, and TI-validated reference design fidelity.

Supply support for ADC122S101EVAL 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 specializing in analog and embedded processing technologies, with leadership in data converters, power management, and interface solutions.

The ADC122S101EVAL belongs to TI's precision data acquisition evaluation platform family, designed to accelerate prototyping and validation of high-fidelity, low-power analog front-ends for industrial and portable measurement applications.

FAQ

What is the primary function of the ADC122S101EVAL?

The ADC122S101EVAL is an evaluation board that hosts the ADC122S101 - a 12-bit, dual-channel, serial-output SAR ADC. Its purpose is to enable hardware and firmware validation of the ADC122S101's performance, including timing compliance, noise floor, INL/DNL, and channel-to-channel crosstalk, using real-world analog sources and host microcontrollers. The board does not contain additional signal conditioning or processing circuitry beyond what is required to operate the ADC122S101.

Does ADC122S101EVAL support both input channels simultaneously?

No - the ADC122S101EVAL supports sequential sampling of IN1 and IN2 via the ADC122S101's internal multiplexer, controlled by the 3-bit ADD[2:0] field in the device's control register. Simultaneous sampling is not supported; the ADC122S101 performs one conversion per CS assertion, selecting either IN1 or IN2 per frame. The board provides independent test points for both inputs to allow rapid reconfiguration between channels during testing.

What power supply requirements must be met to use ADC122S101EVAL?

The ADC122S101EVAL requires a clean, regulated DC supply between 2.7 V and 5.25 V applied to the VA pin, with proper decoupling (1 µF + 0.1 µF) mounted directly on the board. GND must be connected to the system ground plane. No external voltage reference is needed - the ADC122S101 uses VA as its reference, so supply noise directly impacts SNR and THD. TI recommends using a low-noise LDO (e.g., LP2950) rather than a switching regulator for optimal performance.

Can ADC122S101EVAL interface directly with an Arduino or Raspberry Pi?

Yes - the ADC122S101EVAL uses standard SPI signaling (CS, SCLK, DIN, DOUT) compatible with Arduino (using SPI.h library) and Raspberry Pi (via spidev). Pin assignments match common 4-wire SPI conventions: CS → GPIO chip select, SCLK → SCLK, DIN → MOSI, DOUT → MISO. Users must implement correct timing (e.g., SCLK ≤16 MHz, tCSU/tCLH compliance) and send valid 8-bit control words to select IN1 or IN2 before each conversion. Example firmware is available in TI's ADC122S101 product folder.

Is there documentation available for ADC122S101EVAL layout and signal integrity best practices?

Yes - the ADC122S101EVAL user's guide (SLAU225) and schematic (available on ti.com/product/ADC122S101) detail PCB stack-up, ground partitioning, decoupling placement, and critical trace routing rules. Key practices include: separating analog and digital ground planes with single-point connection at GND pin; keeping VA traces short and wide; routing SCLK/CS away from analog inputs; and placing the 1 µF/0.1 µF capacitors ≤1 cm from the VA pin. These reflect TI's validated layout for <1 LSB INL and >72 dB SNR.