3750Vrms isolation in a 4-SOIC footprint
The Toshiba TLP291(GRL-TP,SE is a single-channel DC-input transistor-output optocoupler rated for 3750Vrms isolation, packaged in a 4-SOIC (0.179", 4.55mm width) surface-mount case. It is designed for galvanic isolation in industrial control, power supply feedback, and digital interface applications where the board space is tight but the safety rating is non-negotiable.
CTR binning — the GRL rank at 5mA
The GRL suffix selects a current transfer ratio (CTR) window of 100% to 200%, measured at 5mA forward current. That middle band gives the designer a predictable LED drive current: at 5mA input, the output transistor can sink between 5mA and 10mA (CTR × If). This matters when you are sizing the input-side resistor for a given logic-level threshold or relay coil current. The 100% minimum ensures the opto turns on reliably even with a weak LED drive; the 200% cap prevents saturation delay from getting too long in high-speed switching.
80V output and 50mA per channel
The output transistor is rated for 80V collector-emitter voltage and 50mA continuous output current. That voltage headroom covers 24V and 48V industrial buses with margin; the 50mA limit is typical for driving a logic gate input, a small relay, or a PLC input module. Vce saturation is 300mV max at the rated current, so the voltage drop across the opto is low enough to keep the downstream logic threshold clean.
Switching speed and timing budget
Rise and fall times are 2µs and 3µs typical; turn-on and turn-off times are both 3µs typical. That puts the usable switching frequency around 100 kHz or lower for clean pulse transmission. If you need faster edges for a high-speed serial isolator, this is not the part — but for 50/60 Hz mains zero-cross detection, relay drive, or slow digital isolation, the timing is more than adequate.
Temperature range and environment
The 110°C ceiling is below automotive under-hood requirements (typically 125°C or 150°C), but it covers the vast majority of factory automation and power-supply applications.