**AD7945BRS: A 14-Bit, 250 kSPS Pseudo-Differential SAR ADC for Precision Data Acquisition Systems**

In the realm of precision data acquisition, the choice of analog-to-digital converter (ADC) is paramount, directly influencing system accuracy, noise performance, and power efficiency. The **AD7945BRS from Analog Devices** stands out as a compelling solution, engineered to deliver high performance in a compact package. This 14-bit, 250 kSPS successive approximation register (SAR) ADC is specifically designed for applications demanding **exceptional precision and robust performance** in challenging environments.

At the core of the AD7945BRS is a highly stable SAR architecture, renowned for its **deterministic operation and low latency**. Unlike delta-sigma (ΔΣ) ADCs that require filter settling times, the SAR architecture provides an instantaneous conversion result, making it ideal for multiplexed systems where a single ADC samples multiple channels rapidly. The device's **pseudo-differential input** structure offers a superior alternative to single-ended inputs by providing improved common-mode noise rejection. This feature is particularly valuable in industrial settings where noise from motors, power lines, or other sources can severely degrade measurement accuracy. The pseudo-differential design simplifies the front-end circuitry compared to a fully differential setup while still maintaining a strong defense against common-mode interference.

Power consumption is a critical factor in many modern designs, especially portable and battery-operated equipment. The AD7945BRS addresses this with **ultra-low power dissipation**, consuming a mere 5.5 mW at 250 kSPS and featuring a flexible power-down mode that reduces consumption to 1 μW. This allows designers to optimize systems for power efficiency without sacrificing performance, enabling longer operational life in field instruments and portable medical devices.

The integration of key components further enhances its appeal. The ADC includes a high-speed, 14-bit sampling capacitor DAC and a proprietary charge redistribution network, ensuring excellent linearity with **±0.4 LSB typical integral nonlinearity (INL)** and **±0.3 LSB typical differential nonlinearity (DNL)**. Such stellar linearity minimizes distortion and ensures that the digital output is a faithful representation of the analog input. Furthermore, it incorporates a low-drift, precision 2.5 V internal reference, which eliminates the need for an external reference chip, saving board space and reducing the bill of materials (BOM). For applications requiring an external reference for different input ranges or enhanced accuracy, the internal reference can be easily overridden.

Communication is streamlined through a simple **serial peripheral interface (SPI)**-compatible serial interface, which supports a wide range of logic levels (1.8 V to 5 V) for easy connection to modern microcontrollers and digital signal processors (DSPs). The compact 10-lead MSOP package ensures a small footprint, crucial for space-constrained PCB designs.

Typical applications for the AD7945BRS are vast and include:

* **Industrial Process Control:** PLCs, data loggers, and sensor interfaces.

* **Medical Instrumentation:** Portable patient monitoring and diagnostic equipment.

* **Automotive Systems:** Battery management and sensor monitoring.

* **Communications Infrastructure:** Optical network control loops.

**ICGOO FIND:** The AD7945BRS is a high-performance, low-power SAR ADC that masterfully balances precision, speed, and integration. Its **pseudo-differential input**, **excellent DC accuracy**, and **minimal power requirements** make it an outstanding choice for designers building next-generation precision data acquisition systems across industrial, medical, and automotive markets.

**Keywords:**

1. **Pseudo-Differential Input**

2. **Successive Approximation Register (SAR)**

3. **Ultra-Low Power**

4. **14-Bit Resolution**

5. **Precision Data Acquisition**