AD202JN

The AD202JN is a general-purpose, two-port, transformer-coupled isolation amplifier from Analog Devices. It provides total galvanic isolation between the input and output stages through internal transformer coupling, eliminating the need for an external DC-to-DC converter. This reduces circuit overhead and overall design cost. The device features an uncommitted input amplifier that allows flexible gain configuration, and integrated isolated power outputs that can drive external circuitry on the isolated input side. With an isolation voltage rating of 750Vrms continuous and a maximum common-mode voltage of 1000V, the AD202JN is suitable for demanding industrial and medical applications where patient safety or equipment protection is critical. The device achieves an isolation-mode rejection ratio (IMRR) of 105dB at 60Hz, ensuring excellent rejection of common-mode noise.

The AD202JN uses transformer coupling to achieve galvanic isolation between input and output stages. The input signal is amplified by the uncommitted input amplifier and then modulated onto a carrier signal. This modulated signal passes through the isolation transformer to the output stage, where it is demodulated to reconstruct the original signal. An internal oscillator drives the transformer, which also generates isolated power for the input side circuitry, eliminating the need for an external isolated power supply. The transformer barrier provides the galvanic isolation, with the IMRR determined by the transformer’s capacitive coupling between primary and secondary windings.

• Medical Instrumentation: ECG/EEG front-end isolation for patient safety
• Industrial Process Control: 4-20mA loop isolation and sensor signal conditioning
• Motor Drives: Current sensing via shunt resistor with high-voltage isolation
• Data Acquisition: Multichannel analog input isolation in test systems
• Power Monitoring: High-voltage measurement with galvanic isolation