SP4T switch with 4:1 mux topology
The MAX4518ESD+ is a single-pole four-throw (SP4T) CMOS analog switch configured as a 4:1 multiplexer/demultiplexer. It routes one common I/O to any of four independent channels, or vice versa, with a maximum on-resistance of 100 ohms across the full signal swing. Channel-to-channel matching is held to 4 ohms max, so the insertion loss stays consistent regardless of which path is selected — useful when the mux feeds a downstream ADC or amplifier that expects a stable source impedance.
Signal integrity and switching performance
Crosstalk between channels is -92 dB at 100 kHz, meaning a signal on one channel couples into an adjacent off-channel at roughly 25 µV per volt of signal — negligible for 12-bit systems and workable for many 16-bit precision chains. Charge injection is 5 pC max. When the switch opens, that tiny packet of charge dumps onto the load capacitance; at a 10 pF load it translates to a 500 mV glitch, so keep the downstream capacitance higher or add a sample-and-hold if you're switching into a high-impedance node. Switching times are 150 ns for both turn-on and turn-off, which sets the maximum multiplexing rate at roughly 3.3 MHz before the output doesn't settle. The off-channel leakage is just 100 pA max, so high-impedance sensor inputs won't see a bias shift from the switch.
Runs from a single supply of 2 V to 15 V, or dual supplies of ±2.7 V to ±8 V. That dual-rail option lets the switch pass bipolar signals without a DC bias — handy when you're multiplexing audio or bipolar sensor outputs into a ±5 V ADC front end. The tube packaging means you get a few parts per tube, not a whole reel, which suits prototype runs and small-batch builds.
Fully ROHS3 compliant, so it meets the latest EU restriction directive without exemption claims.