In advanced electronic applications, isolation amplifiers play a pivotal role in maintaining signal integrity and ensuring safety, particularly in high-voltage or noisy environments. These amplifiers—a specific type of differential amplifier—provide essential electrical isolation while amplifying small signals amidst significant common mode voltages. They act as a protective barrier, safeguarding sensitive components from electrical transients and ensuring precise, reliable signal processing. This is vital across a spectrum of applications, from industrial automation to medical equipment, where accurate data transmission and protection against high-voltage interference are critical for system functionality and safety.
Isolation amplifiers employ different methods for signal transfer across electrical isolation barriers. For example, transformer-based isolation amplifiers are notable for their ability to handle high voltages and effectively reject common-mode noise while relying on transformers for signal transmission. Optical isolation amplifiers, on the other hand, rely on light to convey signals, standing out for their rapid response and resistance to electromagnetic interference (EMI). Another type of isolation amplifier is a capacitive isolation amplifier, which uses capacitors for signal transfer and, as a result, offers faster speed and reduced distortion.
Isolation amplifiers find widespread use in critical circuit design. In medical equipment, such as electrocardiogram (EKG/ECG) and electroencephalogram (EEG) machines, they are crucial for ensuring patient safety. Industrial settings, often plagued with high electrical noise or susceptible to ground loops, also rely on these amplifiers. Furthermore, they are essential in data acquisition systems to safeguard data integrity and protect system components from high-voltage transients, underscoring their versatility and importance in modern electronics.
With isolation amplifiers being essential system components where electrical isolation is necessary for safety and signal integrity, measuring their figures of merit (FOM) is crucial to determining each amplifier’s suitability and performance. Their design and type vary based on application requirements, with key FOM specifications focusing on isolation strength, noise rejection, and signal fidelity. Here are some of the most vital FOM measurements for isolation amplifiers:
Our final New Tech Tuesday of 2023 features the Analog Devices ADuM3195 Isolated Amplifiers. These amplifiers represent a significant leap forward in designing advanced electronics, particularly in applications where precision and reliability are paramount.
The ADuM3195 isolated amplifiers (Figure 1), leveraging iCoupler® technology, are designed for high precision in isolated voltage sensing applications. These amplifiers stand out due to their minimal offset and gain error, ensuring accuracy and consistency. They offer a significant advantage over optocoupler-based solutions by maintaining consistent current transfer ratios throughout their lifespan and across a broad temperature range (-40°C to +125°C). The ADuM3195 includes wideband operational amplifiers and two high-accuracy 2.5V reference outputs, enhancing its versatility for various applications. Its robust design, encapsulated in a 16-lead quarter small outline package (QSOP) with a 3000Vrms isolation voltage rating, makes it suitable for demanding environments.
Figure 1: The ADuM3195 includes two wideband operational amplifiers and two high-accuracy 2.5V reference outputs in a 16-lead QSOP for a 3000Vrms isolation voltage rating. (Source: Analog Devices)
A prime use case scenario for these amplifiers is in the field of power supply design. Here, the ADuM3195 stands out due to its ability to provide accurate isolated voltage sensing, a critical requirement in high-voltage power supplies. Unlike traditional amplifiers, the ADuM3195, with its iCoupler technology, offers very low offset and gain error. This level of precision is crucial in applications where even the slightest inaccuracy can lead to significant issues, such as in medical equipment or aerospace electronics.
The advantage of the ADuM3195 over regular amplifiers lies in its robust design, which ensures reliable performance over a wide temperature range and eliminates the uncertainties associated with optocoupler-based solutions. This reliability is especially beneficial in environments where equipment is subjected to extreme conditions.
Additionally, the EVAL-ADUM3195 Evaluation Board from Analog Devices is a game-changer for design engineers. This tool allows for streamlined testing and implementation of the ADuM3195 in various applications. It simplifies the process of integrating these amplifiers into complex systems, ensuring that engineers can fully leverage the ADuM3195's capabilities in their designs.
Isolation amplifiers are a crucial component in advanced electronic applications for ensuring signal integrity and safety, especially in high-voltage or noisy environments. They serve as a protective barrier, shielding sensitive components from electrical transients and guaranteeing precise, dependable signal processing.
In this context, the ADuM3195 from Analog Devices stands out with its iCoupler technology, making it a reliable choice over optocoupler-based solutions. The application of these isolated amplifiers in power supply design underscores their importance in modern electronics, where accuracy and reliability are not just desired but required. Moreover, the EVAL-ADUM3195 Evaluation Board assists design engineers in integrating these amplifiers into complex systems with ease, thus allowing the newest designs to leverage their full suite of capabilities.
Rudy Ramos brings 35+ years of expertise in advanced electromechanical systems, robotics, pneumatics, vacuum systems, high voltage, semiconductor manufacturing, military hardware, and project management. Rudy has authored technical articles appearing in engineering websites and holds a BS in Technical Management and an MBA with a concentration in Project Management. Prior to Mouser, Rudy worked for National Semiconductor and Texas Instruments..