1. Product Overview:

️· Part Number: 54/74LS298
️· Type: 8-Stage Shift Register with 3-State Outputs
️· Function: The 54/74LS298 is a synchronous serial-in, serial-or-parallel-out shift register. It has 8 D-type flip-flops. Data is shifted one stage with each clock pulse. The output can be either serial or parallel.
️· Key Features:
- Synchronous operation
- 3-State outputs (allowing for bus sharing - important for digital systems)
- Versatile: Serial-in, Serial-out or Parallel-out configuration.

2. Pinout and Package Information:

️· Packages: Available in three different packages:
- Case 620-09 (J): 16-Pin Ceramic DIP (Dual In-Line Package)
- Case 751B-03 (D): 16-Pin Plastic SOIC (Small Outline Integrated Circuit)
- Case 648-08 (N): 16-Pin Plastic SOIC
️· Pin Functions (General): (Refer to the diagrams within the datasheet for exact pin assignments, which depend on the specific package)
- Data Input (D): Serial data input.
- Clock Input (C): Clock signal to shift data.
- Output Enables (OE): Active-low enables. When low, the outputs are enabled; when high, the outputs are in a high-impedance state (disconnected).
- Q0-Q7: The 8 output stages.

3. Electrical Characteristics (Key Values - Summarized):

These are critical for proper circuit design.

️· Input HIGH Voltage (VIH): 2.0V - 7.0V (depending on if it's 54 or 74 version)
️· Input LOW Voltage (VIL): 0.8V - 0.7V (depending on if it's 54 or 74 version)
️· Output HIGH Voltage (VOH): Typically 3.5V (VCC = 5.0V)
️· Output LOW Voltage (VOL): Typically 0.35V (VCC = 5.0V)
️· Output Enable Voltage (OE): Typically < 0.4 V (for the active low OE signal to be considered active)
️· Power Supply Voltage (VCC): Typically operates between 3.0V to 6.0V, but most often 5.0V.

4. AC Characteristics (Key Parameters - Summarized):

Important for timing in digital circuits.

️· Propagation Delay (CP to Output): Approximately 21-32ns (depends on temperature) – Time it takes for a clock signal to propagate through the register and appear at the output.
️· Clock Pulse Width (tW): Minimum 20ns – The minimum duration of the clock pulse for reliable operation.
️· Data Setup Time (ts): Minimum 15ns – Time data must be stable *before* the clock edge.
️· Data Hold Time (th): Minimum 5ns – Time data must remain stable *after* the clock edge.

5. Operating Modes & Configurations:

️· Serial-In, Serial-Out: Standard shift register operation.
️· Serial-In, Parallel-Out: Connect all Q0-Q7 outputs to a parallel bus. This allows for faster data transfer from the register.
️· 3-State Operation: Use the output enable (OE) pins to control the state of the outputs. Connect multiple devices to a common bus.

6. Important Considerations & Cautions:

️· 3-State Outputs: Understand how these outputs behave when not actively driving a signal. They effectively disconnect from the circuit.
️· Timing: Carefully analyze the setup and hold times to ensure proper circuit operation.
️· Power Supply: Ensure a stable and clean power supply.
️· Motorola Disclaimer: The datasheet contains a standard disclaimer about product suitability, warranty, and liability.