4541 Programmable Timer with Oscillator

A CD4541 CMOS integrated circuit providing a programmable timer with built-in oscillator. A complete programmable timer with its own oscillator, giving intervals from milliseconds to hours from a single chip and an RC network. Common in long-delay and power-on-reset circuits. Being 4000-series CMOS it runs on anything from 3 to 18 volts, which makes it far more flexible than 5V-only TTL logic and lets it work directly in battery and higher voltage circuits. It also draws almost no current when idle. The trade-off is speed: CMOS of this family is slower than 74HC logic, so it suits control, timing and teaching applications rather than fast data paths. Unused inputs must be tied to a supply rail, never left floating. Wide 3-18V supply range, unlike 5V-only TTL; Extremely low quiescent current suits battery circuits; High noise immunity from the wide logic swing; Standard 14-pin DIP fits breadboards and sockets