What this Darlington optocoupler does for your board
The TLP387(D4-TPR,E is a single-channel DC-input Darlington-output optocoupler from Toshiba, housed in a 6-SOIC surface-mount package with 4 leads. It provides 5000 Vrms of galvanic isolation between the LED side and the photodarlington output, making it a solid choice for industrial controls, PLC I/O modules, and motor-drive interface circuits where noise immunity and safety isolation are required. The minimum current transfer ratio is 1000% at 1 mA forward current.
Output voltage and current — what you can actually drive
The output stage is rated for a maximum collector-emitter voltage of 300 V and can sink up to 150 mA continuously per channel. That means you can directly drive small relays, solenoids, or indicator lamps without an external transistor buffer, saving board space and BOM cost. Switching speed is modest — turn-on time is 50 µs typical, turn-off is 15 µs, with rise and fall times of 40 µs and 15 µs respectively. This part is not for high-frequency PWM or data transmission; it is for on/off control at line-rate or slower, like enabling a power supply or latching a contactor.
Is it still in production? Sourcing and lifecycle
No end-of-life notice or successor has been published by Toshiba, so it remains a safe choice for new designs and ongoing production. It is available in Tape & Reel (TR) or Cut Tape (CT) packaging for the 6-SOIC lead footprint. For volume BOM lines, we source and quote to order against your quantity — no stock-holding claim, but we can confirm availability and pricing at quote time.
Package and footprint — what to expect on the board
The 6-SOIC package has a 0.173-inch body width and 4.40 mm height, with only 4 leads populated — the centre two pins are omitted for creepage distance. The 4-lead layout is standard for high-voltage optocouplers, and the footprint matches common 6-SOIC patterns. Surface-mount assembly is straightforward with standard reflow profiles.