**The AD7868AN: A Comprehensive Overview of Analog Devices' 12-Bit Simultaneous Sampling ADC**

In the realm of data acquisition systems, particularly those involving multi-phase power control, sonar processing, and instrumentation, the ability to capture multiple analog signals at the exact same instant is paramount. **The AD7868AN from Analog Devices stands as a pivotal solution in this space, a high-performance, 12-bit, simultaneous sampling analog-to-digital converter (ADC) engineered for precision and reliability.**

This device integrates four complete ADC channels onto a single monolithic chip. Each channel consists of a sample-and-hold amplifier, a 12-bit ADC, and digital interface logic. **The key feature of the AD7868AN is its true simultaneous sampling capability.** A single CONVERT START command initiates the sampling of all four input channels simultaneously, preserving the precise phase relationship between them. This is a critical advantage over multiplexed ADCs, where a time skew between channel acquisitions can introduce significant errors in phase-sensitive measurements.

Housed in a 44-pin PLCC (Plastic Leaded Chip Carrier) package, the AD7868AN is designed for robust performance. It offers a **throughput rate of up to 450 kSPS aggregate**, meaning it can deliver 450,000 conversion results per second across its four channels. The ADC utilizes a successive approximation architecture, balancing speed with power efficiency. It operates from a single +5 V supply, typically consuming 100 mW of power, and features a flexible power-down mode for reduced energy consumption in portable or battery-powered applications.

The analog inputs are designed for ±10 V or ±5 V bipolar input ranges, selectable by the user, making it versatile for interfacing with a wide array of sensors and signal conditioning circuits. The digital interface is straightforward, with a 14-word data bus for easy connection to microprocessors and digital signal processors (DSPs). The 12-bit data for each channel is provided in two bytes, with four status bits indicating the channel address.

**Applications for the AD7868AN are extensive and varied.** It is exceptionally well-suited for:

* **Multi-axis motor control systems**, where it simultaneously samples currents from multiple phases.

* **Three-phase power monitoring and protection systems**, capturing voltage and current waveforms without phase distortion.

* **Radar and sonar array processing**, where the spatial relationships of received signals are critical.

* **Any industrial or instrumentation system requiring synchronized multi-channel data acquisition.**

In summary, the AD7868AN delivers a potent combination of **simultaneous sampling, high integration, and robust performance**. It eliminates the phase error inherent in multiplexed solutions, providing designers with a reliable and accurate component for complex, multi-channel systems.

**ICGOODFIND:** The AD7868AN is a classic and highly effective solution for engineers designing systems where the precise relative timing between multiple analog channels is non-negotiable. Its integration of four ADCs into one package simplifies design, reduces board space, and ensures accurate, simultaneous data capture for critical applications in industrial control, power, and defense.

**Keywords:**

1. **Simultaneous Sampling ADC**

2. **12-Bit Resolution**

3. **Data Acquisition**

4. **Multi-Channel**

5. **Phase-Sensitive Measurement**