RF signal switching with PhotoMOS isolation
The AQY221N3M1Y is a normally-open single-pole solid-state relay from the PhotoMOS AQY series, designed for low-level AC and DC signal switching including RF paths up to the relay's bandwidth limits. Rated for 150 mA continuous load current across a 0 V to 25 V load voltage range, with a maximum on-state resistance of 7.5 Ohms — the R_on figure sets the insertion loss for the signal path and the self-heating at the rated current.
Package and board integration
Housed in a 4-pin SON package (4-SON, supplier device package code) measuring 2.95 mm on the longest side — a compact footprint for dense PCB layouts where isolation between control and load sides is required. Surface-mount termination with SMD tabs; the tape-and-reel packaging supports automated pick-and-place assembly. The 4-SON body has no exposed thermal pad — the 7.5 Ohm on-resistance at 150 mA dissipates about 170 mW, which the package handles without additional copper area beyond the signal traces.