What this switch does and where it fits
The MAX4661CAE+ is a quad single-pole single-throw normally-closed (SPST-NC) analog switch from Maxim Integrated. Each of the four independent switches connects a common terminal to a normally-closed output when the control logic is low. The part is built for precision signal routing in automated test equipment, data-acquisition systems, and industrial control boards where low on-resistance preserves signal amplitude and reduces self-heating. On-resistance is a maximum 2.5 ohms across the rated supply range, with channel-to-channel matching held to 100 milliohms. That matching matters when you are switching multiple channels in a gain-setting or multiplexer application — the offset between channels stays tight enough to avoid gain errors in the downstream ADC. Single-supply operation from 4.5 V to 36 V, or dual supplies from ±4.5 V to ±20 V. Operating temperature is 0°C to 70°C.
Switching speed and signal integrity
Turn-on time is 275 ns max, turn-off 175 ns max. That is fast enough for relay-replacement in low-frequency switching, audio routing, or sample-and-hold front ends, but not for high-speed digital multiplexing above a few megahertz. Crosstalk is rated at -59 dB at 1 MHz — adequate for separating channels in a multi-channel data-acquisition system without bleeding signal between paths. Charge injection is 300 pC typical. Off-leakage current is 500 pA max, and channel capacitance is 55 pF per side. The low leakage keeps the switch from loading precision analog nodes when off; the capacitance matters for settling time in switched-capacitor filters or when driving long cables.
Package and mounting
Housed in a 16-pin SSOP (0.209-inch body width, 5.30 mm), surface-mount only. The supplier device package is also 16-SSOP. Tube shipment is the listed packaging form — not tape-and-reel, so plan for pick-and-place if you are running high-volume assembly; you will need to transfer to tape or hand-place.
Lifecycle and sourcing
Product status is Active with ROHS3 compliance. No NRND or EOL flags in the record, so this part is safe to specify for new designs and production builds.