PhotoMOS AQY — solid-state relay for signal-level switching
The Panasonic AQY214S is a normally-open solid-state relay from the PhotoMOS AQY series, designed for switching low-level AC or DC signals without mechanical contacts. Rated for 100 mA continuous load current across a 0 V to 400 V output range, it suits applications where galvanic isolation and silent operation matter more than high current capacity.
The 35 Ohm maximum on-state resistance means conduction loss at 100 mA is 0.35 W — well within the SOP package's thermal budget without a heatsink, but the trace width to the drain/source pads should be sized for that dissipation if the relay is continuously on. Supplied in tube packaging; the SOP body is not moisture-sensitive to the same degree as larger QFPs, but standard MSL handling per J-STD-020 applies.
Switching characteristics and signal-chain fit
As a PhotoMOS relay, the AQY214S uses a MOSFET output stage — no contact bounce, no arc, and no wear from repeated switching. This makes it a direct replacement for reed relays in ATE, multiplexers, and data-acquisition front-ends where the 35 Ohm on-resistance is acceptable. The 0-400 V AC/DC output range covers telecom line voltages, 48 V battery rails, and 230 VAC signal monitoring — the 100 mA current ceiling is the limiting factor, not the voltage. Input-to-output isolation is inherent to the PhotoMOS design; the SOP package provides basic isolation suitable for functional separation in signal-level circuits.