Isolation rating and CTR range
The TLP385(GB-TPL,E is a single-channel transistor-output optocoupler from Toshiba, rated for 5000 Vrms isolation — a solid safety margin for industrial bus isolation, motor-drive feedback, and PLC digital inputs where galvanic separation between field and control sides is non-negotiable. The current transfer ratio spans 100% to 600% at a forward current of 5 mA, which means a 5 mA LED drive can saturate the output transistor across the full CTR spread — the 100% floor guarantees the output can sink at least 5 mA, while the 600% ceiling gives headroom for degraded LED output over temperature or life.
Switching speed and output drive
The output transistor can handle up to 80 V collector-emitter and 50 mA continuous current, with a saturation voltage of 300 mV max — the 80 V ceiling suits 24 V and 48 V industrial rails with margin, and the 50 mA output can directly drive a logic gate or a small relay coil without a buffer transistor.
Housed in a 6-SOIC with 4 leads (0.173-inch body width, 4.40 mm height), this surface-mount package is a common footprint for SOIC-4 optocouplers — the 4-lead variant frees up two pins for creepage distance, supporting the 5000 Vrms rating in a compact board area.