Wait, optocouplers have isolation voltages. For example, a high-voltage optocoupler like the H11F1, but again, not matching.
Possible components: High-voltage MOSFET, IGBT, thyristor, or diode. Let's consider a high-voltage diode. If it's a diode, maybe a Zener or a high-voltage rectifier. For example, the 1N5346 is a Zener diode, but that doesn't match. hv490fhb-n80 datasheet
First, I should try to find the datasheet online. Let me do a quick search for "hv490fhb-n80 datasheet". Hmm, the results aren't showing up. Maybe the part doesn't exist under that exact naming, or it's a non-standard part. Perhaps it's a typo or a custom part. Alternatively, maybe it's from a less-known manufacturer or a newer component not widely indexed. Wait, optocouplers have isolation voltages