5000Vrms isolation in a 4-lead 6-SOIC
The Toshiba TLP385(D4GR-TL,E is a single-channel transistor-output optocoupler in a compact 6-SOIC package with 4 leads. The DC input side drives a phototransistor rated for 80V output and 50mA per channel, with a current transfer ratio (CTR) guaranteed between 100% and 300% at a forward current of 5mA.
CTR window and drive margin
The CTR is specified as 100% minimum and 300% maximum at 5mA forward current. That window matters for production yield: a tight CTR range means less variation in the collector current across temperature and over the part's lifetime, so the downstream logic sees a consistent drive level. At 5mA input, the output transistor saturates with a maximum Vce of 300mV, which keeps the logic-low voltage well within TTL or CMOS thresholds.
Temperature range and switching speed
Rated for -55°C to 110°C operating temperature, this optocoupler handles outdoor telecom cabinets, engine-bay auxiliary circuits, and factory-floor sensors without derating. Typical rise and fall times are 2µs and 3µs respectively, with turn-on and turn-off times both at 3µs typical — fast enough for 100 kHz switching power supply feedback loops or isolated serial data at moderate baud rates.
Package and footprint
The 6-SOIC body is 4.40mm wide with 4 populated leads, leaving two unused pins for creepage distance. This package saves board area compared to a DIP-4 while still supporting the 5000Vrms isolation rating.
Lifecycle and compliance
RoHS compliant per the listing, which simplifies EU and UKCA declarations for finished goods. The forward voltage is 1.25V typical, and the maximum DC forward current is 50mA — stay within that to avoid degrading the LED over time.