Isolation barrier and signal transfer
The IL205AT: The 8-SOIC package keeps the creepage distance short, so the isolation voltage is the spec to watch for reinforced insulation in mains-tied equipment. Current transfer ratio runs 40% minimum to 80% maximum at 10 mA forward current. That 2:1 spread means the LED drive current must be set for the low end of the CTR band to guarantee the output saturates over temperature and lifetime — 10 mA into the LED gives you at least 4 mA of collector current at the output transistor, which is enough to pull a 5V logic input low through a 1 kΩ pull-up.
Switching speed and output drive
Turn-on and turn-off times are both 3 µs typical. That 3 µs propagation delay limits the data rate to roughly 115 kHz in a digital isolator role — fine for 24V DC sensor readback at 1 kHz update rates, but too slow for a 1 MHz fieldbus coupler. The transistor-with-base output lets you add a base-emitter resistor to speed up turn-off at the cost of reduced CTR, a trick worth knowing if you need to squeeze 200 kHz out of this part. Output transistor can handle up to 70 V on the collector and saturates at 400 mV max with the base open. That 70 V ceiling covers 48 V industrial rails and 24 V with surge margin; the 400 mV Vce(sat) at 10 mA collector current means the output drops less than half a volt when driving a 5V CMOS input.
Temperature range and forward drive
Operating temperature spans -55°C to 100°C — the -55°C low end covers cold-start in unheated enclosures and outdoor telecom cabinets. The 100°C ceiling is below the 125°C automotive grade, so this part is fit for industrial control cabinets and HVAC panels but not for under-hood engine bay duty without derating the LED current above 85°C. Forward voltage is 1.3 V typical at 10 mA, and the maximum continuous forward current is 60 mA. The 1.3 V Vf means a 3.3 V logic output can drive the LED through a 200 Ω resistor with 10 mA headroom; the 60 mA limit is generous enough that the LED won't limit the design — the CTR spread and thermal derating will.
Active production and compliance
The supplier device package is 8-SOIC, so the land pattern matches industry-standard SOIC-8 with 1.27 mm pitch. RoHS3 compliant per the lifecycle record — no exemption declarations needed for EU BOMs. The input type is DC, meaning the LED is a standard infrared diode, not an AC-input part with anti-parallel diodes; polarity matters on the PCB layout.