**AD7661ACPZ: A 16-Bit, 250 kSPS Pseudo Bipolar SAR ADC for Precision Data Acquisition Systems**

In the realm of precision data acquisition, the choice of an analog-to-digital converter (ADC) is paramount, defining the system's overall accuracy, speed, and reliability. The **AD7661ACPZ from Analog Devices** stands out as a formidable solution, engineered to meet the stringent demands of high-performance applications. This 16-bit, 250 kSPS successive approximation register (SAR) ADC combines high resolution with impressive speed, making it an ideal cornerstone for systems where precision is non-negotiable.

At its core, the AD7661ACPZ is designed around a robust **SAR architecture**, renowned for its precision and inherent simplicity. Unlike delta-sigma (ΔΣ) ADCs, which excel in higher resolution but often trade off speed, the SAR topology provides **deterministic behavior and fast response**, delivering a full 16-bit conversion result without any pipeline delay. This makes it exceptionally suitable for multiplexed applications or systems requiring immediate feedback based on the digital output.

A key feature of this converter is its **pseudo bipolar input range**. This allows the ADC to handle both positive and negative input voltages, typically from -Vref to +Vref, which is critical in industrial and instrumentation systems where signals often swing above and below a common-mode voltage. This functionality provides the flexibility to interface directly with a wide variety of sensors and signal conditioning circuits without requiring complex level-shifting circuitry, thereby simplifying design and enhancing overall system accuracy.

The device achieves its **16-bit resolution without missing codes**, guaranteeing exceptional differential linearity (DNL) and integral linearity (INL). This ensures that every step in the digital output is accurate and consistent, which is vital for precision measurement. Operating at a maximum throughput of **250 kilosamples per second (kSPS)**, it offers a superb balance between speed and resolution, capable of capturing dynamic signals with high fidelity.

Furthermore, the AD7661ACPZ integrates several critical components that streamline system design. It features an on-chip, high-performance **sample-and-hold amplifier** and a precision reference, reducing the bill of materials and layout complexity. Its serial interface (SPI/QSPI™ compatible) facilitates easy connection to modern microcontrollers and digital signal processors (DSPs), while its low-power operation is a significant advantage in portable or power-sensitive equipment.

Applications for this high-performance ADC are vast and varied. It is exceptionally well-suited for:

* **Precision Industrial Instrumentation:** Such as data loggers, PLCs, and test equipment.

* **Medical Imaging and Patient Monitoring:** Where accurate signal acquisition is critical.

* **Spectrum Analysis and Communications Systems:** Benefiting from its combination of speed and resolution.

* **High-Accuracy Automated Test Equipment (ATE):** Demanding the highest levels of DC accuracy.

**ICGOOODFIND:** The AD7661ACPZ is a premier choice for engineers designing high-precision data acquisition systems. Its robust **16-bit SAR architecture**, **pseudo bipolar input capability**, and **250 kSPS throughput** deliver a powerful combination of accuracy, versatility, and speed. By integrating key components and offering a simple serial interface, it significantly reduces design complexity, making it an efficient and reliable solution for the most demanding measurement applications.

**Keywords:** 16-Bit Resolution, SAR ADC, Pseudo Bipolar Input, 250 kSPS, Precision Data Acquisition