74LS145 BCD-to-decimal Decoder/Driver


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. 74LS145 BCD-to-decimal decoder/drivers consist of eight inverters and ten four-input NAND gates. The inverters are connected in pairs to make BCD input data available for decoding by the NAND gates.

74LS145 Features

  • Single BCD-to-Decimal Decoder
  • Inputs Clamped with Schottky Diodes
  • Open Collector Outputs
  • Operating Temperature up to 70°C
  • Standard TTL Switching Voltages

74LS145 Specifications

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

74LS145 Pinout Diagram

74LS145 Pin Description

Pin NoPin NameDescription
1Q0Output pin 0
2Q1Output pin 1
3Q2Output pin 2
4Q3Output pin 3
5Q4Output pin 4
6Q5Output pin 5
7Q6Output pin 6
8GNDGround Pin
9Q7Output pin 7
10Q8Output pin 8
11Q9Output pin 9
12P3BCD Input 3
13P2BCD Input 2
14P1BCD Input 1
15P0BCD Input 0
16VCCPositive Supply


  • It is used in code conversion.  i.e analog to digital conversion in the analog decoder.
  • It may also be used for data distribution.
  • In a high-performance memory system, this decoding can be used to minimize the effect of system decoding.

74LS145 Alternative Equivalent


Download 74LS145 BCD-to-decimal Decoder/Driver Datasheet from the link given below.