AD7503SQ

The AD7503SQ is a CMOS 8-channel analog multiplexer from Analog Devices, part of the AD7501/AD7502/AD7503 family of monolithic multiplexers. This device implements inverted enable logic, meaning a logic high on the enable line disables all channels, while channel selection is controlled via three binary address lines. It operates across the full military temperature range of -55°C to +125°C and is housed in a hermetic ceramic dual-in-line package (CDIP), providing robust physical protection and consistent electrical behavior under thermal and mechanical stress. The multiplexer delivers low on-resistance and minimal leakage currents typical of the family’s dielectric isolation process, and its break-before-make switching architecture prevents transient short-circuits between channels during state changes.

In system design, the AD7503SQ serves data acquisition front-ends, avionics signal routing, military communication switching, and industrial process monitoring where multiple analog sensors or low-level signals are time-multiplexed to a single analog-to-digital converter. The inverted enable characteristic simplifies integration in microprocessor-controlled architectures where an active-low chip select can be derived more naturally. For procurement and sustainment teams, the SQ suffix and CDIP package designate a military-temperature, high-reliability grade component that often finds use in defense and aerospace programs with extended life cycles. As an older legacy device, long-term availability may be constrained, making lifecycle status verification and identification of qualified alternate sources an important part of bill-of-material risk management for extended production or repair commitments.