What the ratings mean for your BOM
The AQY221N3M is a PhotoMOS™ AQY series SPST-NO (1 Form A) solid-state relay rated for 150 mA continuous load current and 0 V to 25 V load voltage — sized for low-power signal switching in ATE, instrumentation, or telecom line cards where a mechanical reed relay's bounce or lifetime would be a constraint.
No official successor order code is listed in the manufacturer's lifecycle records. A functional replacement would require a pin-compatible PhotoMOS relay from the same AQY family with matching 4-SON footprint, SPST-NO configuration, and similar load ratings. Available for sourcing through independent distribution and surplus channels; quantities, pricing, and lot traceability are confirmed at RFQ.
Housed in a 4-SON (small-outline no-lead) package measuring 2.95 mm on the side — a low-profile, leadless SMD footprint suited for dense PCB layouts where height is constrained. Termination style is SMD (SMT) Tab, meaning the drain/source pads are flush with the package bottom; no through-hole or gull-wing leads. The PCB land pattern must match the 4-SON outline with appropriate solder-paste stencil aperture for reliable reflow.