8:3 Encoder 74148

The 8:3 Encoder 74148 is a 74-series 8-line to 3-line priority encoder IC in a 16-pin package. It turns eight input lines into a 3-bit binary code, and when several inputs are active at once it outputs the code of the highest-numbered one. Inputs and outputs are active low, and the enable pins let you cascade two chips into a 16-line encoder.

8:3 Encoder 74148 Specifications

• Function: 8-to-3 line priority encoder
• Inputs: 0–7, active low (input 7 has the highest priority)
• Outputs: A0–A2, active-low binary code
• Control: EI (enable input), EO (enable output), GS (group select)
• Pin map: inputs 4–7 on pins 1–4, inputs 0–3 on pins 10–13; A2, A1, A0 on pins 6, 7, 9; EI 5, GS 14, EO 15
• Pins: 16 (VCC on pin 16, GND on pin 8)
• Supply voltage: 5 V

8:3 Encoder 74148 Applications

• Encoding keypads and switch banks
• Interrupt priority logic
• Turning eight sensor lines into a 3-bit code for a microcontroller
• Digital electronics labs on encoders and decoders
• Cascaded 16-line encoders

What's in the Box

• 1 × 74148 8-to-3 priority encoder IC

Tip: Because the logic is active low, use pull-up resistors on the inputs, connect the switches to GND and tie EI (pin 5) to GND to enable the chip. The outputs are inverted, so when input 7 is active A2 A1 A0 reads 000. Add a 100 nF capacitor between VCC and GND.

Orders placed before 14:00 are ready for pickup the same day. Delivery across Lebanon usually takes 1–3 working days.