PhotoMOS AQY — RF signal switching in a compact SSOP
The AQY221FN2VY is a Panasonic Electric Works PhotoMOS™ AQY series relay, SPST-NO (1 Form A), designed for switching low-level AC or DC signals including RF paths up to 40 V. Rated at 120 mA continuous load current with a maximum on-state resistance of 12.5 Ohms, the relay suits applications where a mechanical relay's contact bounce or limited life would be a problem — test equipment, telecom line cards, and medical sensor front-ends.
Obsolete — sourcing through independent channels
Panasonic has marked the AQY221FN2VY as obsolete. Available through independent surplus and broker channels. The 4-SSOP package and SMD tab termination mean the footprint is shared with other AQY221 variants — a BOM review against the original design's load current and voltage limits is the first step before committing a replacement.
Parametric fit — what the ratings mean for your BOM
120 mA load current at 40 V maximum defines the switching envelope — this relay is sized for signal-level paths, not power. The 12.5 Ohm on-resistance introduces a voltage drop of about 1.5 V at full load, which matters for low-voltage analog or RF signal chains where insertion loss must be budgeted. The 1.3 VDC input threshold means a standard 3.3 V GPIO can drive it directly through a current-limiting resistor — no level translator needed. The SPST-NO form closes the signal path when the input is energised, which is the fail-safe-open configuration for most test and instrumentation switching.