74HC/HCT109 Dual JK flip-flop with set and reset; positive-edge trigger
The 74HC/HCT109 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.
The 74HC/HCT109 are dual positive-edge triggered, JK flip-flops with individual J, K inputs, clock (CP) inputs, set (SD) and reset (RD) inputs; also complementary Q and Q outputs.
The set and reset are asynchronous active LOW inputs and operate independently of the clock input.
The J and K inputs control the state changes of the flip-flops as described in the mode select function table.
The J and K inputs must be stable one set-up time prior to the LOW-to-HIGH clock transition for predictable operation.
The JK design allows operation as a D-type flip-flop by tying the J and K inputs together.
Schmitt-trigger action in the clock input makes the circuit highly tolerant to slower clock rise and fall times.