Dual SPST switch with 4 Ohm on-resistance in 8-uMAX
The MAX4641EUA+ is a dual SPST-NO analog switch from Analog Devices, packing two independent single-pole single-throw normally-open switches into an 8-uMAX/uSOP package. Each channel presents a maximum on-resistance of 4 Ohm, which keeps signal attenuation low in audio, data acquisition, and test equipment paths. Switching is fast — 15 ns turn-on and 8 ns turn-off maximum — so it can handle multiplexed signals in timing-critical applications like ADC front-ends or sample-and-hold circuits without introducing aperture delay.
Signal integrity specs that matter on the bench
Crosstalk between channels is -97 dB at 1 MHz, meaning a signal on one switch channel couples minimally into the other — important when switching low-level analog signals in a mixed-signal system where bleed-through would corrupt the measurement. Charge injection is 2 pC typical. When the switch opens, that tiny packet of charge dumps onto the sampling capacitor — for a 10 nF hold cap it shifts the voltage by 0.2 µV, negligible in most precision circuits but worth knowing if you're switching into a high-impedance node with small hold capacitance. Off-leakage current is 250 pA maximum at 25°C, and channel capacitance is 7 pF on both source and drain sides. The combination sets the bandwidth ceiling: into a 50 Ohm load the -3 dB point is around 450 MHz, though the 4 Ohm on-resistance dominates the insertion loss at lower frequencies. Channel-to-channel on-resistance matching is 200 mOhm max, so both halves of the dual switch track each other closely — useful in differential signal paths or stereo audio where gain mismatch between channels would degrade common-mode rejection.
No negative rail needed — the switch handles signals from ground up to V+. The 8-uMAX package (3.00 mm width MSOP-equivalent) is a compact surface-mount footprint that fits on tight mixed-signal boards. The 0.65 mm pin pitch is layout-friendly with standard 2-layer PCBs.