DG485DJ - 8-Channel SPST Analog Switch Array | Vishay

Eight-Channel Analog Multiplexer

The DG485DJ fits an eight-channel multiplexing arrangement because it contains eight SPST switches connected to a common output, with any combination able to close. A serial controller can select the required input path and route it to the shared output. The 55 ohm typical on-resistance and 85 ohm maximum rating should be included when assessing source impedance and acceptable attenuation. With its 170 ns typical turn-on time, the device can also serve systems that need faster switching than mechanical relays. Designers should establish whether one or several channels may conduct simultaneously and verify that the connected sources do not create unacceptable signal interaction. The 16-DIP format also makes the device straightforward to use in through-hole prototype and legacy instrumentation hardware.

Data-Acquisition Signal Routing

DG485DJ is appropriate for data-acquisition front ends that need to route several analog inputs through a controlled common path. Its rail-to-rail analog input range, eight SPST channels, and 55 ohm typical on-resistance support the basic requirements of many low-to-moderate-bandwidth measurement systems. The 170 ns typical turn-on time can shorten selection delays when the acquisition system changes channels rapidly. Source impedance remains important because the closed-switch resistance adds directly to the signal path and can cause attenuation. Measurement accuracy should therefore be characterized with the actual sensor, amplifier, cable, and ADC input network. The Vishay Siliconix datasheet also identifies low signal distortion, making the device relevant to precision routing where switching transients must remain small.

Audio Signal Routing

The DG485DJ can route audio signals among multiple sources when the design requires compact electronic channel selection and does not require galvanic isolation. Its eight SPST switches share a common output, while the 55 ohm typical on-resistance can be suitable for low-impedance audio paths. The rail-to-rail analog input range and low-signal-distortion feature support the broad signal excursions encountered in line-level routing, although the manufacturer should be consulted for exact amplitude and distortion limits. The 170 ns typical turn-on time is far faster than a mechanical relay, helping reduce switching dead time between sources. Keep traces short, maintain a low-impedance ground reference, and test for audible clicks or crosstalk when switching signals with significant DC content.

Process-Control Interface

DG485DJ suits process-control equipment that must select sensed or controlled analog signals through a shared output. The eight-channel SPST arrangement simplifies multiplexing, and TTL- and CMOS-compatible control enables integration with common digital control logic. Its rail-to-rail input range supports operation across much of the available signal range, while 55 ohm typical on-resistance must be weighed against the input impedance of downstream instrumentation. Because the device is a semiconductor switch rather than an isolation barrier, do not assume that it provides the reinforced isolation required by many industrial safety circuits. Confirm loop grounding, fault conditions, settling requirements, and isolation boundaries in the final process-control architecture. Its 16-DIP package supports both prototype construction and established through-hole control boards.

Automated Test Equipment

The DG485DJ can connect multiple test points or signal sources to a common instrument input in automated test equipment. Eight independently addressable SPST paths reduce the number of external relays or manually selected fixtures, while the 170 ns typical turn-on time supports faster test sequencing. The closed-channel resistance of 55 ohm typical may affect very high-impedance or precision measurements, so characterize it within the complete fixture architecture. Low signal distortion helps preserve the integrity of small test signals, and the ability to chain devices can extend routing capacity when several DG485DJ parts are controlled in sequence. Designers should evaluate settling time, crosstalk, switch capacitance, and contact-noise effects at the frequencies used by the test set.

Legacy Instrumentation Control

DG485DJ is well suited to legacy instrumentation and control boards that use through-hole DIP logic and require multiple analog inputs selected by a controller. The 16-DIP package is straightforward to inspect, socket, and replace, which can simplify maintenance compared with fine-pitch surface-mount switch arrays. Its serial control reduces the number of separate control lines required to operate eight SPST paths, and TTL compatibility supports integration with established digital logic families. The rail-to-rail input range provides useful signal flexibility. Engineers should use the manufacturer pin-description table for board-level connections, add stable supply bypassing, and preserve analog ground routing. Where field replacement or long product lifetimes matter, confirm the active status, recommended operating conditions, and long-term availability before committing the design.