What this part is and where it fits
The CD4049UBD is a hex inverter from the 4000B CMOS logic family, containing six independent inverter gates each with a single input. It operates from a 3V to 18V supply range, making it suitable for battery-powered or unregulated-rail designs where a 5V-only gate would drop out. The -55°C to 125°C temperature grade qualifies it for military, avionics, downhole, and outdoor industrial environments where the board sees extreme thermal cycling.
Key ratings and what they mean for your BOM
The 3V to 18V supply range is the headline feature — it lets this inverter work from a 3.6V Li-ion cell down to near depletion, or from a 12V industrial rail without a regulator. The 4 µA quiescent current (max) keeps the standby draw negligible in battery-backed systems. Output drive is asymmetric: 4.3 mA sourcing and 24 mA sinking at rated supply, which means it can directly drive a low-power LED or a CMOS input but not a relay coil without a buffer. Propagation delay is 50 ns at 15V with a 50 pF load — that is about 10x slower than a 74AC gate, so it is a poor fit for high-speed clock trees or fast bus interfaces, but perfectly adequate for panel switch debounce, level translation, or enable logic running below a few MHz.
Package and footprint
The CD4049UBD is supplied in a 16-pin SOIC package (0.154" body width, 3.90 mm) with a surface-mount footprint. The supplier device package is 16-SOIC. This is a standard SOIC-16 layout shared across many 4000B and 74HC series parts, so the PCB footprint is well-established and easy to route. No exposed pad — thermal management is straightforward for a CMOS gate drawing microamps.
Lifecycle and sourcing reality
There is no last-time-buy or obsolescence risk on this line. The 4000B series has been manufactured for decades and remains a staple for low-speed, wide-voltage, high-temperature logic. For dual-sourcing resilience, the CD4049UBD is a standard 4000B inverter — functionally equivalent to other manufacturers' 4049UB devices in the same package, though pin compatibility should be verified against the specific alternate order code.