800 V off-state — what it means for AC switching
The VOT8121AM-VT is a single-channel phototriac optocoupler from the VOT8121 family, designed for isolated AC load switching in industrial and appliance controls. Its 800 V off-state voltage rating gives comfortable margin for 240 V AC line switching (peak ~340 V) and even 277 V AC (peak ~392 V), with headroom for transient spikes. The output is a Triac rated for 100 mA RMS on-state current — sized for low-power loads like solid-state relays, small solenoids, or triac gate drives.
No zero-crossing — expect random-phase turn-on
This part has no zero-crossing circuit, meaning the Triac fires immediately when the LED current exceeds the 10 mA trigger threshold, regardless of the AC line phase. That gives you random-phase turn-on, useful for phase-angle dimming or fast switching where you cannot wait for the next zero-cross. If your design requires zero-cross switching to reduce inrush or EMI, you would look at a different variant in the VOT8121 family that includes that feature.
1 kV/µs dV/dt — false-trigger immunity in noisy environments
The minimum static dV/dt of 1 kV/µs means the output Triac will not falsely trigger from fast voltage transients on the AC line — common in motor drives, relay coil switching, or inductive load environments. This is a key parameter for reliability in industrial panels or HVAC controls where line noise is the norm.
Temperature range and isolation
The 3750 Vrms isolation voltage meets reinforced insulation requirements for safety-rated AC mains interfaces, backed by cUR, UR, and VDE approvals.
Package and ordering options
Supplied in a 4-pin SOP Gull Wing surface-mount package (4-SMD, Gull Wing; supplier device package 4-SOP). Available in Tape & Reel (TR) for automated pick-and-place or Cut Tape (CT) for prototype and low-volume builds. The forward voltage is 1.15 V typical, with a maximum LED drive current of 50 mA; hold current is 250 µA typical.
Lifecycle and compliance
ROHS3 compliant, with cUR, UR, and VDE agency approvals.