5000Vrms isolation in a 4-pin SOIC — what it buys the BOM
The Toshiba TLP385(GRH,E is a single-channel transistor-output optocoupler in a 6-SOIC package with only 4 leads populated. Its headline rating is 5000Vrms isolation — enough to meet reinforced insulation requirements in mains-connected industrial PSUs, motor drives, and PLC I/O modules without needing a second device in series. The current transfer ratio is specified as a range: 150% minimum to 300% maximum, both measured at 5 mA forward current. That guarantees at least 7.5 mA collector current from a 5 mA LED drive, which is enough to saturate a logic input directly without a transistor buffer. The 300% ceiling means the designer must account for the variation in the feedback loop gain budget — no surprise if the CTR lands anywhere in that band.
Switching speed and output drive — where the limits sit
Rise and fall times are 2 µs and 3 µs typical; turn-on and turn-off times are both 3 µs typical. That puts this part in the general-purpose isolation class — fine for 10 kHz PWM or serial data at 115.2 kbps, but not for high-speed digital isolation above 1 Mbps. The output transistor is rated for 80 V and 50 mA continuous, which covers 24 V industrial logic and low-power relay drives. Vce saturation is 300 mV max at the rated output current — clean logic-level swing when driving a 5 V or 3.3 V input. The forward voltage is 1.25 V typical, so a 3.3 V supply with a 220 Ω series resistor delivers the 5 mA test current comfortably.
Temperature range and package — field-fit check
Rated for -55°C to 110°C operating temperature, which covers the industrial range with headroom into cold-start automotive cabin environments. The 6-SOIC-4 package (0.173" body width, 4.40 mm) is a compact surface-mount footprint that fits on dense I/O cards. Tube shipment suits low-to-medium volume assembly; the TLP385(GRH-TPR,E variant moves to tape-and-reel for high-speed pick-and-place.
Lifecycle and compliance — no supply risk
RoHS compliant per the listing. The TLP385(GRH,E is the standard CTR grade (150-300%); the sibling TLP385(GRL,E carries a 50-150% CTR band, and the TLP385(GB,E offers a 100-200% band — all otherwise identical in pinout and ratings. For dual-source flexibility, any of these CTR grades can be qualified into the same board footprint.