The H11A817B3S is officially listed as Obsolete by onsemi, meaning the manufacturer has ceased production and no further factory orders are accepted.
Parametric profile and board-fit
Single-channel transistor-output optocoupler in a 4-SMD Gull Wing package (supplier device package 4-SMD). Current transfer ratio (CTR) is specified at 130% minimum and 260% maximum at If=5mA, giving a tight bin that reduces design margin uncertainty in logic-level translation or feedback loops. The 70V output breakdown and 50mA continuous output current suit 24V logic rails and low-side switching loads. Operating temperature range of -55°C to +100°C covers industrial and some automotive under-hood environments. Rise and fall times of 2.4µs typical limit the switching frequency to roughly 100 kHz — sufficient for PWM feedback and serial isolation below that rate.