4511 BCD-to-7-Segment Latch/Decoder/Driver

A CD4511 CMOS integrated circuit providing a BCD to 7-segment latch, decoder and driver. Takes a 4-bit BCD input and drives a seven-segment display directly, with a latch to hold the displayed value. It also has enough output drive for the LEDs, which is why it needs no external transistors. A staple of digital display projects. 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 16-pin DIP fits breadboards and sockets