74ls73 dip ic

🔹 74LS73 / SN74LS73N – Dual JK Flip-Flop with Clear (DIP-14)

A TTL integrated circuit containing two independent, negative-edge-triggered JK flip-flops, each with an individual asynchronous clear (reset) input. It is a fundamental building block for digital counters, frequency dividers, shift registers, and memory elements in classic digital logic systems.

✅ Specifications:

• Part Number: 74LS73, SN74LS73N (DIP package)

• Type: Dual JK Master-Slave Flip-Flop

• Logic Family: TTL (Low-Power Schottky)

• Supply Voltage (Vcc): 5V ±5% (4.75V to 5.25V)

• Number of Circuits: 2 independent flip-flops

• Trigger Type: Negative-Edge Triggered (Clock High-to-Low transition)

• Inputs per Flip-Flop:

  • J, K: Data inputs

  • CLK̅: Clock input (active on falling edge)

  • CLR̅: Asynchronous Clear input (Active LOW, overrides all other inputs)

• Outputs per Flip-Flop: Q and Q̅ (Complementary outputs)

• Truth Table (per flip-flop, on falling CLK edge):

  CLR̅	J	K	Q(next)	Action
  L	X	X	L	Asynchronous Clear (Reset)
  H	L	L	Q	Hold (No Change)
  H	L	H	L	Reset
  H	H	L	H	Set
  H	H	H	Q̅	Toggle (Divide-by-2)

• Max Clock Frequency: ~30 MHz (typical)

• Propagation Delay (CLK to Q): ~20ns (typical)

• Package: DIP-14 (Dual In-Line, 14-pin, through-hole)

• Operating Temperature: 0°C to +70°C (Commercial)

⚙️ Key Features:

• Dual Independent Flip-Flops: Contains two complete, separate JK flip-flops in one package.

• Asynchronous Clear: Each flip-flop can be instantly reset (to LOW) regardless of the clock state.

• Complementary Outputs: Provides both the true (Q) and inverted (Q̅) outputs.

• Toggle Mode: When J=K=1, the output toggles on each clock pulse, enabling counter/divider functions.

• Classic Logic Design: A staple component in 1970s-1990s digital logic education and design.

📦 Typical Applications:

• Frequency Dividers: Each flip-flop can divide a clock frequency by 2 (in toggle mode). Cascading creates divide-by-4, -8, etc.

• Ripple Counters: Building blocks for simple asynchronous counters.

• Shift Registers: Used in serial-in/parallel-out or parallel-in/serial-out data storage.

• Data Synchronization & Debouncing: Capturing and cleaning up asynchronous digital signals.

• State Machine Logic: Basic memory elements in finite state machine (FSM) design.

• Retro Computing & Educational Kits: Found in classic computer and digital trainer boards.

🔧 Pinout (DIP-14):

• Pin 1: CLK̅ 1 – Clock input for Flip-Flop 1

• Pin 2: CLR̅ 1 – Clear input for Flip-Flop 1

• Pin 3: J 1 – J input for Flip-Flop 1

• Pin 4: VCC (+5V)

• Pin 5: K 1 – K input for Flip-Flop 1

• Pin 6: Q̅ 1 – Inverted output for Flip-Flop 1

• Pin 7: Q 1 – True output for Flip-Flop 1

• Pin 8: Q 2 – True output for Flip-Flop 2

• Pin 9: Q̅ 2 – Inverted output for Flip-Flop 2

• Pin 10: K 2 – K input for Flip-Flop 2

• Pin 11: GND

• Pin 12: J 2 – J input for Flip-Flop 2

• Pin 13: CLR̅ 2 – Clear input for Flip-Flop 2

• Pin 14: CLK̅ 2 – Clock input for Flip-Flop 2

⚠️ Important Design Notes & Limitations:

• Negative-Edge Triggering: The flip-flop captures input data on the falling edge (HIGH-to-LOW transition) of the clock. This is crucial for timing diagrams.

• Asynchronous Clear Dominates: When CLR̅ is LOW, the output Q is forced LOW immediately, overriding J, K, and CLK.

• Setup/Hold Time: For reliable operation, J and K inputs must be stable before and after the clock’s falling edge (typical setup time ~20ns, hold time ~0ns).

• Unused Inputs: Never leave TTL inputs floating. Tie unused J, K inputs HIGH (to Vcc via a 1kΩ resistor) or LOW (to GND). Tie unused CLR̅ inputs HIGH.

• Power Supply Decoupling: Always use a 0.1µF ceramic capacitor between VCC (pin 4) and GND (pin 11).

• Modern Alternatives: For new designs, consider 74HC73 (CMOS, same pinout) or microcontroller-based logic.