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
Typical rise and fall times are 2 µs and 3 µs respectively, with turn-on and turn-off times both at 3 µs — this puts the practical switching ceiling around 100 kHz for pulse-width signals, adequate for relay coil drives, AC mains zero-cross detection, and low-speed serial isolation. 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.
Package and temperature grade
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. Rated for -55°C to 110°C operating temperature, the TLP385(GB-TPL,E fits into outdoor telecom cabinets, engine-bay electronics, and factory-floor enclosures where the ambient can swing well beyond commercial limits.