4170Vrms isolation with a 63-125% CTR window
The onsemi CNY17F2SM is a single-channel transistor-output optocoupler in the 6-SMD gull wing package. Its 4170Vrms isolation rating means this part provides reinforced isolation for applications where the safety barrier must withstand a 4.17 kV RMS test voltage — typical for mains-referenced circuits in industrial power supplies, motor drives, and PLC digital inputs. This bounded CTR range guarantees the output transistor drives the load within a predictable collector current window — critical for ensuring the downstream logic sees a valid high level across temperature and LED aging without saturating the phototransistor. Switching is specified with a 2µs turn-on and 3µs turn-off time typical, and a 4µs rise / 3.5µs fall time maximum. These figures place the CNY17F2SM in the medium-speed class for optocouplers — adequate for 50/60 Hz line synchronization, relay drivers, and status feedback at PLC scan rates, but not for high-speed data links.
This is a current-production part, not an NRND or EOL line — no last-time-buy window or successor cross-reference is needed. The base product number is CNY17F2 — the SM suffix denotes the 6-SMD gull wing package variant.
The 6-SMD gull wing package (supplier device package 6-SMD) is a surface-mount form factor with a 1.27 mm pitch typical for this class. The gull wing leads provide visual solder-joint inspection access and self-centering during reflow. Maximum forward current is 60 mA DC, and the typical forward voltage is 1.35V at the test current.