The IC 4518 is a Dual BCD Up Counter, comprising two identical, internally synchronous 4-stage counters. Each counter stage is composed of D-type flip-flops that allow interchangeable CLK and EN lines. Thus enabling incrementing on either the positive or negative transition. The IC 4518 provides advantageous features such as high noise immunity and low thermal dissipation.

It comes in a 16-pin hermetically sealed package and can be easily interfaced with TTL, CMOS, and NMOS devices. The counter can be cascaded in the ripple mode by connecting Q4 to the enable input of the subsequent counter while holding the CLOCK input of the latter low. This allows for efficient and flexible counter-cascading.