74LS148 8 to 3 Priority Encoder


The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC. The 74LS148 encodes eight data lines to three-line (9-7-6) BCD. The implied decimal zero condition does not require an input condition because zero is encoded when all eight data lines are at a high logic level.

74LS148 Features

  • Encodes Eight Data Lines to Three (octal)
  • Inputs Clamped with Schottky Diodes
  • Low Power
  • Operating Temperature up to 70°C
  • Standard TTL Switching Voltages

74LS148 Specifications

Supply Voltage4.75 – 5.25Vdc
Maximum Clock Frequency40Mhz
Power Dissipation2mW/gate @100kHz
Minimum Output Current8mA
Propagation Delay10nS
Fan Out (TTL Loads)20

74LS148 Pinout Diagram

74LS148 Pin Description

Pin NoPin NameDescription
14Data Input Pin 4
25Data Input Pin 5
36Data Input Pin 6
47Data Input Pin 7
5EIEnable Input Pin
6A2Output A2
7A1Output A1
9A0Output A0
100Data Input Pin 0
111Data Input Pin 1
122Data Input Pin 2
133Data Input Pin 3
14GSOutput GS
15E0Enable Output Pin
16VCCPositive Supply

74LS148 Circuit

Below is a simple circuit of 4 to 2 Bit Encoder using logic gates (NOT, NOR, and AND).


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74LS148 Alternative Equivalent


Download 74LS148 8 to 3 Priority Encoder Datasheet from the link given below.