HD74HC78

HD74HC78 Dual J-K Flip-Flops (with Preset, Common Clear and Common Clock) Description This flip-flop is edge sensitive to the clock input and change state on the negative transition of the clock pulse. Each flip-flop has independent J, K, and preset inputs and Q and Q outputs. Two flip-flops are controlled by a common clear and a common clock. Preset and clear are independent of the clock and accomplished by a low logic level on the corresponding input. Features High Speed Operation: tpd (Clock to Q) = 20 ns typ (CL = 50 pF) High Output Current: Fanout of 10 LSTTL Loads Wide Operating Voltage: VCC = 2 to 6 V Low Input Current: 1 µA max Low Quiescent Supply Current: ICC (static) = 2 µA max (Ta = 25°C) HD74HC78 Function Table Inputs Preset L H L H H H H H H H Note: Clear H L L H H H H H H H L H Clock X X X J X X X L L H H X X X K X X X L H L H X X X Outputs Q H L H* 1 Q L H H*1 No change L H Toggle No change No change No change H L 1. Q and Q will remain HIGH as long as Preset and Clear are Low, but Q and Q are unpredictable, if Preset and Clear go HIGH simultaneously. Pin Arrangement CK 1 1PR 2 1J 3 VCC 4 CLR 5 2PR 6 2K 7 (Top view) K CK J CLR PR Q Q K CK J CLR PR Q Q 14 1K 13 1Q 12 1Q 11 GND 10 2J 9 2Q 8 2Q 2 HD74HC78 Block Diagram (1//2) To Other FF PR CLR J K # CK CK # CK # CK CK CK CK CK # CK CK # CK Q Q CK CK To Other FF 3 HD74HC78 DC Characteristics Ta = 25°C Item Input voltage Symbol VIH Ta = –40 to +85°C Max — — — 0.5 1.35 1.8 — — — — — 0.1 ...