Signal routing with 35 Ohm on-resistance and -86 dB crosstalk
The DG419LDY+ is a single-pole double-throw (SPDT) analog switch from Analog Devices, built for routing analog or digital signals in precision measurement, audio, and data-acquisition chains. Crosstalk is specified at -86 dB at 1 MHz, meaning a signal on one channel couples into the off channel at roughly 50 µV per volt of signal — low enough for 12-bit systems switching audio or low-frequency sensor data without a dedicated guard trace.
Supply flexibility and charge injection for sample-and-hold
The switch operates from a single 9 V to 36 V rail or dual ±4.5 V to ±20 V supplies, so it fits both single-supply data-acquisition front-ends and bipolar signal chains where the analog ground is a virtual midpoint. Charge injection is 15 pC typical — when the switch opens, that charge dumps into the sampling capacitor. In a 12-bit, 100 kSPS SAR ADC with a 10 nF hold cap, the injected charge creates a 1.5 mV step, which settles within the LSB budget if the acquisition time is long enough. Off-leakage current is 250 pA max, and channel capacitance is 8 pF on both source and drain pins. The low leakage keeps the voltage on a high-impedance node from drifting more than a few millivolts over a 10 ms hold interval.
Package and board integration
The 2:1 multiplexer/demultiplexer circuit means one common pin connects to either of two I/O pins — useful for selecting between two sensor inputs or routing a single ADC input to one of two signal paths.