SN74LS148D

The SN74LS148D is a high-speed, low-power priority encoder integrated circuit (IC) produced by Texas Instruments. It belongs to the 74LS (Low Power Schottky) series, which is known for its fast switching times and reduced power consumption compared to earlier TTL (Transistor-Transistor Logic) families.

Key Features:

1. Functionality: The SN74LS148D encodes the highest-priority active input into a binary code. It has eight active-low inputs (I0 to I7) and produces a 3-bit binary output (Y0 to Y2) corresponding to the highest priority input that is active. If no inputs are active, the outputs will indicate a specific state.

2. Priority Encoding: The device prioritizes inputs I7 through I0, with I7 having the highest priority. This means that if multiple inputs are active, the output will reflect the highest-numbered active input.

3. Active-Low Outputs: The outputs are active-low, meaning that a logic '0' indicates the presence of an active input, while a logic '1' indicates that the input is inactive.

4. Enable and Output Control: The SN74LS148D features an active-low enable input (G), which allows the device to be disabled. When G is high, the outputs are in a high-impedance state, effectively disconnecting the encoder from the circuit.

5. Pin Configuration: The IC is typically housed in a 16-pin dual in-line package (DIP) or surface-mount package. The pins include the eight input pins (I0 to I7), three output pins (Y0 to Y2), the enable pin (G), and additional pins for carry-out (C) and priority output (A).

6. Electrical Characteristics: The SN74LS148D operates with a supply voltage (Vcc) typically ranging from 4.75V to 5.25V. It has a maximum propagation delay of around 10 nanoseconds, making it suitable for high-speed applications.

7. Applications: This encoder is commonly used in applications such as data multiplexing, priority encoding in digital systems, and as part of larger digital circuits where the identification of the highest priority signal is necessary.

8. Temperature Range: The device is designed to operate over a wide temperature range, typically from -40°C to +85°C, making it suitable for various industrial and consumer applications.

Summary:

The SN74LS148D is a versatile and efficient priority encoder that provides a compact solution for encoding multiple inputs into a binary format. Its low power consumption, high-speed operation, and ease of integration into digital systems make it a popular choice for engineers and designers working on complex electronic projects.