Single-channel optocoupler with 5000Vrms isolation
The Vishay TCDT1122G is a single-channel, transistor-output optocoupler in a 6-DIP through-hole package. It provides galvanic isolation rated at 5000Vrms, with a guaranteed current transfer ratio (CTR) between 63% and 125% at a forward current of 10mA. The output transistor can handle up to 70V collector-emitter voltage and 50mA continuous current, with a maximum saturation voltage of 300mV.
CTR range and LED drive design
The 63% to 125% CTR bin at 10mA If gives the designer a predictable gain window for the optocoupler. A minimum CTR of 63% means the output transistor will sink at least 6.3mA collector current with 10mA LED drive, which is enough to pull a logic input low or drive a small relay coil. The 125% maximum prevents overdrive saturation issues in feedback loops. This tight binning reduces the need for external gain trimming across production lots.
Output ratings and switching capability
With a 70V Vce(max) and 50mA continuous output current, the TCDT1122G can switch industrial-level signals directly — 24V PLC inputs, 12V logic rails, or low-power DC loads. The 300mV Vce(sat) at rated current keeps power dissipation low in the output stage. The DC input type means it is designed for steady-state or low-frequency switching, not high-speed data transmission.
Package and mounting
Housed in a standard 6-DIP package with 0.400-inch (10.16mm) pin spacing, the TCDT1122G is a through-hole device suited for prototyping, low-volume production, and rework-friendly designs.