**AD9618JR: A Comprehensive Technical Overview of the 10-Bit, 20 MSPS Monolithic A/D Converter**

The **AD9618JR** from Analog Devices represents a significant milestone in the evolution of high-speed, monolithic analog-to-digital converters (ADCs). As a **10-bit resolution**, **20 Mega Samples Per Second (MSPS)** ADC, it is engineered to deliver a critical balance of speed, accuracy, and power efficiency for a wide array of data acquisition and signal processing applications. This converter integrates all necessary components, including a track-and-hold amplifier and a reference voltage, onto a single monolithic chip, simplifying system design and enhancing reliability.

At the core of the AD9618JR's performance is its advanced **bipolar complementary metal-oxide-semiconductor (BiCMOS)** process technology. This fabrication technique allows the device to achieve a remarkable combination of the high-speed switching characteristics of bipolar transistors and the low-power, high-density integration benefits of CMOS technology. The result is a converter capable of **20 MSPS sampling rates** while maintaining exceptional linearity and dynamic performance.

A key performance metric for any ADC is its signal integrity. The AD9618JR excels here with a typical **Spurious-Free Dynamic Range (SFDR)** of **-68 dB** and a **Signal-to-Noise Ratio (SNR)** of **58 dB** at a 10 MHz input frequency. These figures ensure that the digitized output is a highly accurate representation of the analog input, even when processing complex waveforms. The device features a proprietary input structure that minimizes distortion, making it suitable for demanding applications like imaging systems, instrumentation, and telecommunications.

The **on-chip track-and-hold (T/H) amplifier** is a critical feature that enables this high-fidelity conversion. It acquires the input signal in a minuscule aperture time, effectively "freezing" fast-changing analog signals for accurate digitization. This allows the AD9618JR to accurately convert input frequencies up to and beyond the Nyquist limit (10 MHz for a 20 MSPS ADC). Furthermore, the integrated **voltage reference** provides a stable and accurate basis for conversion, eliminating the need for external components and their associated drift and board space requirements.

From an interface perspective, the AD9618JR is designed for ease of use. It provides **standard binary output coding** and features parallel TTL/CMOS-compatible output drivers, ensuring straightforward connection to modern DSPs, FPGAs, and microprocessors. Its **±0.5 LSB differential non-linearity (DNL)** and **±0.75 LSB integral non-linearity (INL)** guarantee no missing codes and excellent linearity across its entire operating range.

Operating from a single **+5V power supply** and consuming a modest **175 mW of power**, the AD9618JR offers an excellent performance-to-power ratio. Its 28-pin SOIC package (denoted by the "JR" suffix) is industry-standard, facilitating both prototyping and high-volume manufacturing. Designed with robustness in mind, it is well-suited for applications in **medical imaging, radar systems, high-speed data acquisition cards, and professional video equipment**.

**ICGOODFIND:** The AD9618JR stands as a robust and highly integrated solution for medium-speed, high-accuracy conversion needs. Its monolithic design, excellent dynamic performance, and low power consumption make it a compelling choice for system designers seeking to simplify their analog front-end without compromising on speed or signal fidelity.

**Keywords:** Monolithic ADC, 10-Bit Resolution, 20 MSPS, BiCMOS Process, Signal-to-Noise Ratio (SNR)