35 Ohm SPDT switch for precision analog signal routing
The Maxim Integrated MAX319CPA+ is a single-pole double-throw (SPDT) CMOS analog switch in an 8-pin PDIP through-hole package. With a maximum on-resistance of 35 Ohm, it is designed for low-distortion switching of analog signals in applications such as audio routing, data acquisition, instrumentation, and test equipment. The part operates from either a dual supply of ±4.5 V to ±20 V or a single supply of 10 V to 30 V, giving the designer flexibility to match existing rail voltages without extra level translation.
Turn-on time is 175 ns max, turn-off 145 ns max. That is fast enough for audio-band multiplexing, relay replacement, and low-frequency analog switching, but not intended for high-speed digital or RF paths where sub-10 ns switching is required. Charge injection is 3 pC typ – a moderate figure that can cause a glitch on the output when switching; in high-impedance sample-and-hold circuits or precision integrators, budget for a settling-time penalty or add a downstream buffer.
Crosstalk and channel matching – isolation in multi-channel designs
Crosstalk is -85 dB at 1 MHz. Channel-to-channel on-resistance matching is 2 Ohm max.
Leakage and capacitance – impact on high-impedance nodes
Off-state leakage current is 250 pA max, negligible in most circuits but worth noting if the switch is used in a high-impedance sensor interface or a long-hold sample-and-hold where picoamp-level leakage can cause droop. Channel capacitance (source off, drain off) is 8 pF each – a moderate load that will not significantly load a 10 kOhm source but will roll off bandwidth above 10 MHz.