Three manufacturers have issued end-of-life notice on long-running logic families in the last quarter. The affected part numbers stretch across 4000-series CMOS logic, older RS-232 interface devices and through-hole variants still used in industrial control.
Why these notices matter more than they look
These parts are typically low value and high consequence. A 40-cent logic gate can stop a controller board that has been in the field for a decade, and the replacement often requires a layout change if the package is obsolete as well as the die.
Options, in order of cost
- Last-time-buy: secure the remaining-life requirement now, held in bonded or hub storage and released against schedule.
- Approved alternate: cross-reference to a current-production equivalent, then qualify package, temperature and timing differences before commit.
- Board redesign: usually the most expensive path and should be scheduled against the LTB window, not discovered after it closes.
The window is the constraint
Last-time-buy windows are typically six to nine months from the notice, and they close whether or not the forecast is complete. Our advice is to place the analysis on the calendar the week the notice arrives.