CD4013

CD4013 is a dual D-type flip-flop from the CMOS CD4000 family. Each of the two identical flip-flops provides a data input (D), a clock input (CLK), an output (Q) and its complement (Q'), and asynchronous direct-set (PRE) and direct-reset (CLR) inputs. The devices are edge-triggered, typically responding to the rising edge of the clock; when PRE and CLR are both deasserted (logic high), the state of Q follows D at the clock edge. Asynchronous PRE, when asserted (low), forces Q high and Q' low; asynchronous CLR, when asserted, forces Q low and Q' high. If both PRE and CLR are asserted simultaneously, the outputs may be undefined.

The CD4013 is widely used as memory elements, counters, and toggles. A classic configuration is to connect D to the complement of Q (D = Q') so that each clock edge toggles Q, effectively a divide-by-two. Its independent sections allow crafting of two separate flip-flops in one package, often used in timing and state machines. The device operates over a broad supply range typical of the CD4000 family (commonly 3 to 15 volts) with low static power consumption. It comes in standard CMOS packages such as DIP-14 and small-outline packages.

Manufactured by multiple vendors, the CD4013 remains popular for simple, low-power logic tasks where robust static operation is valued over ultra-high speed. When using PRE and CLR, care should be taken to avoid keeping both asserted for extended periods or violating input timing requirements, to prevent metastability or indeterminate outputs.