5300 Vrms isolation in a 4-DIP through-hole package
The Vishay VO618A-2 is a single-channel optoisolator with a DC input and a phototransistor output, housed in a standard 4-DIP (0.300", 7.62mm) through-hole package. Its 5300 Vrms isolation rating is the key spec for any design requiring reinforced insulation between a low-voltage control side and a higher-voltage load side — think motor-drive IGBT gate drive, PLC digital inputs, or medical patient-isolation barriers. The through-hole DIP package suits manual assembly or sockets in prototype and low-volume production runs.
CTR at 1 mA — what the 63% to 125% range means for your drive circuit
The current transfer ratio is specified at a forward current of 1 mA, with a minimum of 63% and a maximum of 125%. That 63% floor is the number to design around: it tells you that with 1 mA through the LED, the output transistor can sink at least 630 µA of collector current. If your downstream logic input needs 1 mA to guarantee a low state, you need to increase the LED drive — or pick a part with a higher CTR min. The 125% ceiling matters for saturation margin: a high-CTR unit might saturate harder, but the 400 mV Vce(sat) max keeps the voltage drop predictable across the batch.
Switching speed: 2 µs rise/fall, 3 µs turn-on, 2.3 µs turn-off
Typical rise and fall times are 2 µs each, with turn-on at 3 µs and turn-off at 2.3 µs. That puts this part in the medium-speed class — fine for 10 kHz PWM or 115.2 kbps serial isolation, but not for high-speed gate drive or fast data links. The 80 V collector-emitter rating and 50 mA output current per channel give you headroom for driving small relays, DC solenoids, or logic-level loads directly.
Temperature range and environment
Rated for -55°C to 110°C operating temperature, the VO618A-2 covers industrial and outdoor equipment — motor drives, solar inverters, HVAC controllers — where the ambient inside the enclosure can hit 85°C and self-heating adds another 15-20°C. The 60 mA absolute-maximum LED forward current and 400 mV Vce(sat) max hold across the full range, though CTR typically drops at cold temperatures; factor in the 63% min at 25°C and derate further if your system must switch at -40°C.
Lifecycle and compliance
For dual-sourcing flexibility, the VO618A family includes pin-compatible CTR-graded variants — the VO618A-2 sits in the middle of the CTR range; the VO618A-3 offers a higher min CTR if your design needs more output current at the same 1 mA LED drive.