Dual JK flip-flop in a 16-pin DIP — what it does and where it fits
The Texas Instruments CD74HC109E is a dual JK flip-flop from the 74HC high-speed CMOS logic family. Each of the two elements stores one bit, triggered on the positive edge of the clock, with complementary Q and Q-not outputs. A set (preset) and reset input per flip-flop lets you force the output state independent of the clock. The part is built for through-hole assembly in a 16-pin DIP package (0.300" body, 7.62 mm pitch), making it a drop-in fit for breadboards, prototype boards, and legacy PCB layouts that still use DIP footprints. Operating temperature range is -55°C to 125°C. Supply voltage spans 2V to 6V. Quiescent current is 4 µA.
60 MHz clock — timing margin for fast logic
Maximum clock frequency is 60 MHz. Propagation delay is 31 ns at 6V with 50 pF load.
Output drive and fan-out
Each output can source or sink 5.2 mA, enough to drive one or two standard HC loads directly. For driving LEDs, relays, or long PCB traces, add a buffer or transistor stage. Input capacitance is 10 pF per input — light enough that a single HC gate can drive several flip-flops without signal degradation.
Lifecycle and sourcing — still in active production
The CD74HC109E is listed as Active with ROHS3 compliance.