The TC74HC148AF(TP1) 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 (TP1) suffix often indicates a specific packing or testing variation.

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: Allows for quick processing and prioritization of inputs.
• Low Power Consumption: Reduces energy consumption in various applications.
• High Noise Immunity: Provides reliable operation in noisy environments.
• Wide Operating Voltage: Offers flexibility in power supply selection.
• Cascading Capability: Enables expansion of the number of inputs.
• Group Select Output: Facilitates detection of active inputs.

Additional Details

The TC74HC148AF(TP1) is supplied in a 16-pin package. The priority is assigned based on the input number, with input 0 having the lowest priority and input 7 having the highest. The device provides a straightforward way to implement priority encoding in systems where multiple inputs need to be prioritized and processed sequentially. The operating temperature range is -40°C to +85°C. The active low inputs simplify external logic for signaling input requests.