2. SI8719BC-A-IS Substitution Conclusion This part is entirely unsuitable as a replacement due to a severe deficiency in speed performance. The primary discrepancy lies in its data rate, which is only 15Mbps compared to the original's 100Mbps. Additionally, its propagation delay (50ns) and pulse width distortion (25ns) are an order of magnitude greater. This device cannot handle any moderate- to high-speed digital signals (e.g., UART or SPI at higher baud rates), which would directly cause communication errors or disrupt system timing. Although it offers higher isolation voltage, its low-speed nature confines it to isolating very low-frequency signals where timing is non-critical. This application profile is completely mismatched with the original part's intended use case.