**AD7628KR: A 16-Bit, 18 MSPS Pseudo Differential SAR ADC for High-Speed Precision Data Acquisition Systems**

In the realm of high-performance data acquisition, the ability to accurately digitize analog signals at high speeds is paramount. The **AD7628KR from Analog Devices** stands as a pivotal solution, engineered to meet the rigorous demands of advanced imaging, communications, and instrumentation systems. This 16-bit, 18 MSPS successive approximation register (SAR) analog-to-digital converter (ADC) combines exceptional speed with precision, establishing a new benchmark in its class.

At the core of the AD7628KR is a highly optimized SAR architecture, renowned for its deterministic operation and low latency. Unlike delta-sigma (ΔΣ) ADCs that require filter settling times, SAR ADCs provide instant conversion results, making them ideal for applications requiring rapid control loops or real-time signal processing. The device achieves a remarkable **18 MSPS sampling rate while maintaining 16-bit resolution**, ensuring minimal noise and distortion even at elevated speeds. This is complemented by its **pseudo differential input structure**, which offers a practical balance between fully differential and single-ended designs. It provides improved common-mode noise rejection over single-ended inputs—a critical feature in electrically noisy environments—while simplifying the front-end design compared to fully differential configurations.

Key performance metrics underscore the converter’s capabilities. The AD7628KR delivers outstanding **AC performance**, including a typical signal-to-noise ratio (SNR) of 91 dB and spurious-free dynamic range (SFDR) of 100 dB at 1 MHz input frequency, ensuring high-fidelity digitization of fast-changing signals. Its **DC precision** is equally impressive, with ±0.3 LSB integral nonlinearity (INL) and ±0.25 LSB differential nonlinearity (DNL), guaranteeing accurate representation of analog inputs with minimal error.

The device incorporates a range of features designed to enhance system integration and flexibility. An internal conversion clock and reference buffer reduce external component count, saving board space and design complexity. The digital interface is compatible with both 1.8 V and 3.3 V logic families, facilitating easy connection to modern FPGAs, ASICs, or microprocessors. Furthermore, its **low power dissipation of 100 mW at 18 MSPS** makes it suitable for power-sensitive applications without compromising performance.

Target applications span several high-stakes industries. In medical imaging systems such as MRI and CT scanners, the AD7628KR provides the necessary speed and resolution to capture detailed anatomical data. Within communications infrastructure, it enables precise signal processing in software-defined radios and radar systems. Industrial automation leverages its accuracy for high-speed control and measurement, while test and equipment manufacturers utilize it to build high-performance oscilloscopes and spectrum analyzers.

Despite its advanced capabilities, designers must consider several factors to maximize performance. Implementing adequate decoupling and grounding techniques is essential to maintain signal integrity. Although the pseudo differential input simplifies design, careful attention to PCB layout and source impedance matching is recommended to mitigate noise. Additionally, the selection of an appropriate drive amplifier—such as the ADA4899-1—is crucial to preserve the ADC’s dynamic range and linearity.

**ICGOODFIND**: The AD7628KR is a superior 16-bit SAR ADC that merges high speed (18 MSPS) with precision, offering excellent noise performance and system integration features. Its pseudo differential input architecture provides a practical advantage for robust data acquisition in challenging environments, making it an optimal choice for cutting-edge applications across medical, communications, and industrial sectors.

**Keywords**:

**High-Speed Data Acquisition**, **16-Bit Resolution**, **SAR ADC Architecture**, **Pseudo Differential Input**, **Low Power Dissipation**