Four SPST switches with Beyond-the-Rails™ overvoltage tolerance
The MAX14777GTP+ from Maxim Integrated packs four normally-open SPST analog switches into a 20-TQFN package, each channel rated for 10 Ohm max on-resistance with 200 mOhm channel-to-channel matching. The Beyond-the-Rails™ series means the signal path can swing above the 3 V to 5.5 V supply rail without the part latching up — a practical advantage when an industrial sensor output drifts past the ADC supply headroom. With 380 MHz -3 dB bandwidth and -101 dB crosstalk at 100 kHz, this part handles composite video, high-speed ADC input multiplexing, or RF signal routing where channel isolation matters. The 225 pC charge injection figure tells you how much glitch gets dumped into a hold capacitor on switching — factor that into your sample-and-hold settling budget.
What the ratings mean on a BOM line
The 10 Ohm on-resistance is the series resistance the signal sees through the switch — at 10 mA signal current that is a 100 mV drop, so budget it in your gain path. The 200 mOhm channel matching means all four channels track within that window, which keeps gain errors consistent across multiplexed channels. Off-leakage sits at 20 nA max, and each channel presents 12 pF of capacitance to the signal when off — both low enough for 12-bit precision multiplexing at moderate impedance. The 40 µs turn-on and 100 µs turn-off times are not fast enough for high-speed switching but work fine for audio routing, sensor scanning, or relay replacement where the mechanical contact bounce was the bottleneck anyway.
Package and environment for field deployment
The 20-TQFN (4x4 mm) with exposed pad needs a thermal via stitch under the paddle if you plan to push continuous current through all four channels — the package ceiling, not the per-channel limit, governs total dissipation. Surface-mount only, so no socket swap in the field; plan for rework with a hot-air station. The -40°C to 105°C operating range covers outdoor telecom cabinets, factory floor enclosures, and under-hood automotive auxiliary electronics. ROHS3 compliant, no lead in the finish.
Sourcing and lifecycle
For volume production commitments, the supply posture is stable with no LTB risk visible. If you are dual-sourcing, look for pin-compatible SPST x4 switches in the same 20-TQFN footprint from other vendors — but the Beyond-the-Rails™ overvoltage tolerance is specific to this Maxim series and not guaranteed on generic alternatives.