Quad SPST-NC switch with 4 Ohm max on-resistance
The Maxim MAX4664CSE+ is a quad single-pole single-throw normally-closed (SPST-NC) analog switch in a 16-pin SOIC package. Each of the four independent switches presents a maximum on-resistance of 4 Ohms, with channel-to-channel matching held to 200 mOhms — tight enough for precision gain-setting or multiplexing low-level analog signals without introducing offset errors between paths. Switching is fast: Ton 275 ns max, Toff 175 ns max, which keeps the throughput window open for 1 MHz+ sample rates in data acquisition or audio routing. Crosstalk between channels is specified at -60 dB at 1 MHz, giving clean separation for multi-channel sensor muxes or analog front ends. Supply range covers single +4.5 V to +36 V, or dual ±4.5 V to ±20 V. Charge injection is 300 pC typical. The 16-SOIC footprint (0.154" body width, 3.90 mm) is a standard surface-mount package that routes easily on two-layer boards.
The 4 Ohm max on-resistance keeps voltage drop across the switch below 4 mV per mA of signal current, which is negligible for most op-amp level signals. If you are switching a precision voltage reference or a DAC output, that 4 Ohm in series with the load forms a voltage divider — account for it in the gain budget, or use the matching spec (200 mOhm max) to guarantee the error is consistent across channels. Off-leakage is 500 pA max. Channel capacitance is 34 pF.