Single-channel optocoupler with 3750Vrms isolation
The Toshiba TLP293(BL,E is a single-channel transistor-output optocoupler in a 4-SOIC surface-mount package. It provides 3750Vrms galvanic isolation between a DC input LED and a phototransistor output, with a current transfer ratio (CTR) guaranteed between 200% and 600% at a forward current of 5mA. The output transistor is rated for up to 80V and 50mA continuous, with a typical Vce saturation of 300mV. Switching is specified with 2µs rise and 3µs fall times, and turn-on/turn-off times of 3µs each.
CTR range and drive margin
The 200% minimum CTR at 5mA forward current means the output transistor can sink at least 10mA with 5mA LED drive, leaving healthy margin for degraded LED output over temperature or life. The 600% maximum CTR gives a wide window for design — no need to over-drive the LED to guarantee saturation, and the 300mV Vce(sat) keeps dissipation low in the on-state.
Package and rework notes
Housed in a 4-SOIC (0.179" body width, 4.55mm) — the same footprint as a standard SOIC-4 optocoupler. The 4-SO package is a low-profile, small-outline style with 1.27mm pin pitch. The small body and exposed leads make it hand-reworkable with a hot-air station; the 4-pin count means orientation is easy to verify before reflow.