1. Bandwidth and Slew Rate: The OPA1642 offers a substantially higher gain-bandwidth product (11 MHz) and slew rate (20 V/µs) compared to the AD822 (1.9 MHz, 3 V/µs). This makes the OPA1642 suitable for high-frequency audio signal processing or applications requiring fast transient response, whereas the AD822 is better suited for low-frequency or DC precision amplification. 2. Input Offset Voltage: The AD822 features a much lower offset voltage (400 µV) than the OPA1642 (1 mV), giving it a clear advantage in applications demanding high DC accuracy, such as sensor signal conditioning. 3. Quiescent Current and Output Drive: The OPA1642 draws higher quiescent current and provides stronger output current capability (36 mA vs. 20 mA), making it suitable for driving lower impedance loads. The AD822 has lower quiescent current, which benefits low-power systems, but its drive capability is more limited. 4. Application Focus: The OPA1642 is classified as an "audio operational amplifier," optimized for low-distortion, low-noise audio signal chains. The AD822 is a "general-purpose precision op-amp," emphasizing DC accuracy and stability. Their internal designs—including compensation networks and transistor biasing—are optimized for different frequency domains. Direct substitution could lead to degraded high-frequency performance or increased audio distortion.