The TC74HC148AF-EL is a high-speed CMOS 8-input priority encoder fabricated with silicon gate CMOS technology. It encodes eight data input lines (0-7) to a three-line (A0-A2) binary output, corresponding to the highest priority active low input. It includes input enable (EI) and output enable (EO) for device cascading, and group select (GS) for indicating when one or more inputs are active. The '-EL' suffix often indicates a specific packaging or reel size for automated assembly.

Applications

• Keyboard encoding
• Priority interrupt controllers
• Data multiplexing
• Industrial control systems
• Computer peripherals

Features

• High-speed operation: tpd = 15 ns (typ.) at VCC = 5V
• Low power dissipation: ICC = 4 μA (max) at Ta = 25°C
• High noise immunity: VNIH = VNIL = 28 % VCC (min)
• Output drive capability: 10 LSTTL loads
• Symmetrical output impedance: |IOH| = IOL = 4 mA (min)
• Balanced propagation delays: tPLH ≈ tPHL
• Wide operating voltage range: VCC = 2 to 6 V
• Input Enable (EI) and Output Enable (EO) for cascading
• Group Select (GS) output indicates active inputs

Benefits

• High Speed: Enables quick processing and prioritization of inputs.
• Low Power Consumption: Suitable for energy-efficient applications.
• High Noise Immunity: Ensures reliable operation in electrically noisy environments.
• Wide Operating Voltage: Provides flexibility in power supply design.
• Cascading Capability: Allows expansion of input capacity.
• Group Select Output: Simplifies the detection of active inputs.

Additional Details

The TC74HC148AF-EL comes in a 16-pin package. Priority is assigned based on the input number, with input 7 having the highest priority and input 0 the lowest. The active low inputs can simplify external request logic. The operating temperature range is -40°C to +85°C. The -EL suffix implies the part is supplied in a format optimal for automated assembly processes.