**AD7868AR: A Comprehensive Guide to Analog Devices' 8-Channel 12-Bit Simultaneous Sampling ADC**

In the world of data acquisition systems, particularly those dealing with multi-phase power control, motor control, or instrumentation, the ability to capture multiple analog signals at the exact same instant is paramount. The **AD7868AR from Analog Devices** stands as a pivotal solution in this domain, integrating high performance with critical functionality. This comprehensive guide delves into the architecture, key features, and typical applications of this powerful analog-to-digital converter (ADC).

The AD7868AR is a **12-bit, 8-channel, simultaneous sampling ADC**. Its core capability lies in its innovative design, which includes eight track/hold amplifiers—one for each analog input channel. This architecture is the key to its simultaneous sampling prowess. Unlike multiplexed ADCs that sequentially sample channels, introducing phase delays, the AD7868AR can capture a snapshot of all eight input voltages at a single point in time. This ensures the **preservation of critical phase information** between channels, which is essential for accurate power calculations and vector analysis in poly-phase systems.

Housed in a compact 28-lead SOIC package (denoted by the "AR" suffix), the device is designed for robust performance. It operates from a single +5 V power supply and features a high-speed parallel interface for efficient data transfer. The ADC can be configured to sample its inputs based on a CONVST (convert start) signal. Upon conversion completion, the results for all channels are stored in an internal register array, accessible by the host processor. The AD7868AR offers impressive throughput, capable of achieving a **100 kSPS sampling rate per channel**, resulting in an aggregate throughput of 800 kSPS when all channels are used.

A significant advantage of the AD7868AR is its flexibility. Users can select which channels to sample through software control, making it efficient for applications that may not always require all eight inputs. Furthermore, it offers both **software and hardware conversion initiation** modes, providing designers with options to integrate it seamlessly into various system architectures. The device also includes a versatile power-down mode, significantly reducing power consumption in portable or battery-operated equipment when not actively converting.

The applications for the AD7868AR are extensive and critical. It is exceptionally well-suited for:

* **Poly-phase Motor Control and Drives:** Precisely measuring all three phase currents and voltages simultaneously for accurate control algorithms.

* **Multi-axis Positioning Systems:** Sampling feedback from multiple sensors at the same time to coordinate movement.

* **Power Quality Monitoring and Power Protection Systems:** Analyzing harmonic content and monitoring phase relationships in real-time.

* **Data Acquisition Systems (DAQ):** Any application requiring time-correlated data from multiple sensors, such as in vibration analysis or physics experiments.

**ICGOODFIND:**

The AD7868AR is a cornerstone component for engineers designing systems where **simultaneous acquisition of multiple analog signals** is non-negotiable. Its integration of eight track/hold amplifiers, **12-bit resolution**, and **high channel count** into a single package provides a reliable, high-performance, and space-efficient solution. For projects demanding accurate phase-sensitive measurements across several channels, the AD7868AR remains a highly compelling choice from Analog Devices' extensive portfolio.

**Keywords:**

Simultaneous Sampling ADC

12-Bit Resolution

8-Channel

Data Acquisition System

Motor Control