Isolation barrier and CTR margins
The CNY173SVM provides 4170Vrms isolation between input and output — a reinforced insulation rating suitable for mains-isolated feedback loops, PLC digital inputs, and motor-drive interface circuits where the safety barrier must survive surge without breakdown. Current transfer ratio is specified at 100% minimum and 200% maximum, both measured at If=10 mA. That 2:1 spread means the design must guarantee the output transistor saturates at the low end while not exceeding the LED absolute-maximum forward current at the high end — a 1.35V typical Vf helps keep the LED drive within a 5V logic rail.
Switching speed and output drive
Turn-on time is 2 µs typical, turn-off 3 µs typical, with rise/fall times of 4 µs and 3.5 µs maximum. This is fast enough for 10–20 kHz PWM feedback or serial data up to 115 kbps, but not for high-speed isolated comms — that domain calls for a digital isolator or a logic-output optocoupler. The output transistor is rated for 70 V maximum collector-emitter voltage and 50 mA continuous current. With a 400 mV max Vce(sat), it can drive a 5V logic input directly through a 1–2 kΩ pull-up without an external buffer.
Package and assembly fit
The gull-wing leads allow visual inspection of solder joints — a practical advantage for prototype builds and low-volume production where X-ray inspection is not routine. The input is DC-coupled (Input Type: DC), so the LED polarity matters — reverse connection blocks current and the output stays off. No internal reverse-protection diode; the BOM should include a series resistor and, for noisy environments, a reverse parallel diode across the input.
The base product number CNY173 covers multiple CTR and package variants — the SVM suffix denotes the 6-SMD Gull Wing package in Bulk tube. The -40°C to 100°C operating temperature range qualifies the part for industrial environments — outdoor telecom cabinets, factory-floor PLC racks, and motor-drive junction boxes where commercial-grade optocouplers would drift out of CTR spec.