SPDT switch with 4 Ohm flatness
The MAX4644EUA+ is a single-pole double-throw (SPDT) analog switch from Analog Devices, configured as a 2:1 multiplexer/demultiplexer in a single circuit. Its 4 Ohm maximum on-resistance with 100 mOhm channel-to-channel matching keeps the insertion loss consistent across the signal path — important for precision analog routing where gain error from switch resistance matters.
15 ns switching with -82 dB isolation
Turn-on time is 15 ns maximum, turn-off 5 ns maximum, so the switch can handle fast multiplexing in data-acquisition front-ends without introducing timing skew between channels. Crosstalk is -82 dB at 1 MHz, meaning the off-channel signal couples into the active path at less than 80 µV for a 1 V swing — adequate for 12-bit systems switching audio or low-frequency sensor signals. Charge injection is 5 pC typical, which translates to a voltage glitch of about 0.4 mV into a 10 nF hold capacitor — this sets the pedestal error in a sample-and-hold circuit. Off-leakage current is 250 pA maximum at 25 °C, rising with temperature but still compatible with high-impedance inputs like pH probes or photodiode amplifiers. Channel capacitance is 12 pF on both the source and drain sides, so the -3 dB bandwidth into a 50 Ohm load is roughly 265 MHz — the switch does not limit the signal path in sub-100 MHz applications.