Isolation barrier and output type
The TLP591B(C,F) is a single-channel photovoltaic optoisolator from Toshiba Semiconductor, rated for 2500Vrms isolation between input and output — enough for basic isolation in low-voltage DC circuits where reinforced isolation is not required.
The 200µs turn-on and 3ms turn-off times are slow by modern standards; this is a DC-level or low-frequency switch, not a PWM or data isolator. The 24µA output current per channel sets the load ceiling: driving a standard MOSFET gate directly is fine; driving a relay coil or a logic input with significant pull-down current needs a buffer.
Package and lifecycle posture
The through-hole 6-DIP (0.300", 7.62mm) package with 5 leads is a legacy form factor — easy to hand-solder, rework, and inspect, but consumes more board area than a surface-mount alternative. RoHS compliant with no lead-free finish exemption flagged, so it fits standard Pb-free assembly flows.
Sourcing and compliance note
For a through-hole photovoltaic optoisolator with this temperature range, the TLP591B(C,F) is a straightforward choice — confirm the 5-lead DIP footprint and the 24µA output budget before committing.