74LS154 4-Line To 16-Line Decoder/Demultiplexer IC DIP-24

74LS154 4-Line To 16-Line Decoder/Demultiplexer IC DIP-24 is a versatile, high-speed integrated circuit designed to convert a 4-bit binary input code into 16 mutually exclusive active-low outputs. This decoder IC significantly simplifies address decoding and data routing tasks in complex digital systems. It functions as a single-chip solution for selecting one of 16 possible output lines based on the 4-bit input address (A, B, C, D). Furthermore, the 74LS154 features two active-low enable inputs ($\text{G1}$ and $\text{G2}$) which must both be held low to enable the outputs. Consequently, this capability provides exceptional flexibility for cascading multiple decoders or strobing the decoded outputs. Use this TTL component to efficiently manage memory addressing, sequence counter outputs, or drive display segments in your next digital project.

Key Features:

• High Decoding Capability: This single chip selects one of 16 possible output lines from a 4-bit binary input code (4:16 decoding).
• Active-Low Outputs: All 16 output lines ($\text{Y}_{0}$ through $\text{Y}_{15}$) are active-low, meaning the selected line goes low (L) while all unselected lines remain high (H).
• Dual Enable Inputs: Includes two active-low enable pins ($\overline{\text{G1}}$ and $\overline{\text{G2}}$), offering easy system expansion and synchronous control of the chip’s output.
• Low Power Schottky (LS) Technology: Utilizes LS technology, which provides relatively high speed while maintaining low power consumption compared to older TTL families.
• Demultiplexing Functionality: The chip can effectively function as a 1-line to 16-line demultiplexer by using one enable line as a data input and the other as a strobe input.

Technical Specifications:

• Logic Family: LS (Low Power Schottky TTL)
• Input Voltage (High Level $\text{V}_{\text{IH}}$): Minimum 2.0 V
• Input Voltage (Low Level $\text{V}_{\text{IL}}$): Maximum 0.8 V
• Output Voltage (High Level $\text{V}_{\text{OH}}$): Minimum $\text{V}_{\text{CC}}$ − 2.0 V
• Output Voltage (Low Level $\text{V}_{\text{OL}}$): Maximum 0.4 V
• Supply Voltage ($\text{V}_{\text{CC}}$): 4.75 V to 5.25 V (Nominal 5.0 V)
• Maximum Propagation Delay: Typically 20 ns (Data to Output)

Mechanical Specifications:

• Package Type: DIP-24 (Dual In-line Package, Through-Hole)
• Material: Plastic Encapsulated IC
• Number of Pins: 24
• Pin Pitch: 2.54 mm (0.1 inch)

Dimensions:

• Body Length: ≈ 31.75 mm (1.25 inches)
• Body Width: ≈ 14.0 mm (0.55 inches)
• Row Spacing: 15.24 mm (0.6 inches wide)
• Lead Material: Tinned Copper Alloy

Pinout and Wiring:

• Address Inputs ($\text{A}, \text{B}, \text{C}, \text{D}$): Connect these 4 pins to the binary address lines (D is the most significant bit).
• Enable Inputs ($\overline{\text{G1}}, \overline{\text{G2}}$): Both must be held low (L) to enable the output decoding function. If either is high (H), all 16 outputs remain high.
• Outputs ($\text{Y}_{0}$ to $\text{Y}_{15}$): These 16 active-low pins are where the decoded signal appears. Only one output will be low at a time when the chip is enabled.
• $\text{V}_{\text{CC}}$ (Pin 24): Connect to the +5V power supply.
• GND (Pin 12): Connect to the circuit ground reference.

Datasheet Reference:

• Download Texas Instruments SN74LS154 Datasheet

Commonly Used in:

• Microprocessor Systems: Critical for selecting memory chips or I/O ports based on address bus values.
• Digital Data Routing: Used for distributing a single data stream (demultiplexing) to one of 16 different paths.
• LED and Display Drivers: Efficiently managing the selection and activation of large numbers of LED segments or indicators.

Applications:

• Memory Address Decoding: Implementing chip select logic in retro computing or embedded memory architectures.
• Sequential Control: Creating complex step sequences in state machines or industrial controllers.
• Code Conversion: Translating a 4-bit code into 16 distinct control signals.
• Data Distribution: Utilizing the demultiplexer function to route a data stream to the correct output destination.

Equivalent Models:

• SN74LS154 (Texas Instruments): The original and common part number for the LS family version.
• 74HC154 (High Speed CMOS): A functionally identical, low-power, high-speed CMOS version, which is often a modern replacement. However, check input logic level compatibility.
• DM74LS154 (Fairchild/National Semiconductor): A manufacturer-specific prefix for the same 4-to-16 line decoder.

Package Includes:

• 1 x 74LS154 4-Line To 16-Line Decoder/Demultiplexer IC DIP-24