SPST-NO solid-state relay for 400 V signal switching
The AQY214EHAZ is a normally-open (1 Form A) solid-state relay from the PhotoMOS AQY series, rated to switch AC or DC loads up to 120 mA across a 0 V to 400 V range — the 400 V blocking voltage suits high-side signal isolation in test equipment, industrial I/O modules, and battery-monitoring front ends where a mechanical relay's contact wear is unacceptable. The 35 Ohm max on-state resistance is the thermal budget driver: at 120 mA the self-heating is I²R = 0.5 W, which the 4-SMD package dissipates into the PCB copper plane.
4-SMD gull-wing — footprint and board integration
Housed in a 4-SMD package with a 7.62 mm (0.300") body width and gull-wing leads, the AQY214EHAZ mates with standard SOIC-4 land patterns. The gull-wing form allows visual solder-joint inspection and rework with a hot-air station — no bottom-side pad like a QFN. Cut Tape works for prototype runs.