600 V off-state SCR output for AC-load switching
The Toshiba TLP748J(D4,F) is a single-channel SCR-output optoisolator in a through-hole 6-DIP package. It provides 4000 Vrms of isolation between the LED input and the SCR output, with a 600 V off-state voltage rating that suits it for switching AC loads up to 150 mA RMS on-state current. The 5 V/µs minimum static dV/dt immunity helps prevent false triggering in the presence of fast voltage transients common on mains-powered industrial equipment.
Turn-on time and trigger sensitivity
With a typical turn-on time of 15 µs and a maximum LED trigger current of 10 mA, this part is designed for direct drive from logic-level signals or microcontroller I/O pins. The 1.15 V typical forward voltage and 50 mA maximum DC forward current give a reasonable LED drive budget. Once triggered, the SCR latches on until the holding current of 1 mA is interrupted — no zero-crossing circuit is included, so the output turns on immediately regardless of the AC line phase.
Industrial temperature range and approvals
Safety approvals from BSI, SEMKO, UR, and VDE cover the 4000 Vrms isolation rating, simplifying compliance for equipment sold into European and North American markets.