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SN74LS161 / 74ls161AN replacement chip. DIP 16,  4-Bit Synchronous Binary Counter.


SN74LS161 replacement chip. DIP 16,  4-Bit Synchronous Binary Counter.

The 74LS161 is a 4-bit binary counter IC (integrated circuit) that is commonly used in digital electronic circuits. It belongs to the TTL (Transistor-Transistor Logic) family of ICs and is widely used in various applications, including digital counters, frequency dividers, and general-purpose digital systems.

Here are some key features and characteristics of the 74LS161:

  1. Number of Counting Bits: The 74LS161 is a 4-bit counter, meaning it can count in binary from 0000 (binary) to 1111 (binary).
  2. Counting Modes: It can operate in either a synchronous or asynchronous counting mode. In synchronous mode, all the bits of the counter change state simultaneously, whereas in asynchronous mode, the bits change state one at a time.
  3. Parallel Load (Load) Input: This input allows you to preset the counter to a specific binary value by applying the desired input to the parallel data inputs (D0, D1, D2, D3) and then asserting the LOAD input.
  4. Clock (CLK) Input: The clock input is used to advance the counter on each clock pulse. In synchronous mode, the counter responds to the clock input, while in asynchronous mode, the counter advances on each rising edge of the clock signal.
  5. Clear (CLR) Input: This input is used to clear the counter to zero. When CLR is asserted, all the outputs become low.
  6. Ripple Carry Output (RCO): The 74LS161 has a ripple carry output that can be connected to the clock input of another 74LS161 or similar counter to expand the counting capability.
  7. Carry Look-Ahead (CLA): The 74LS161 features carry look-ahead functionality, which helps improve the speed of carry propagation in cascaded counters.
  8. Power Supply: Typically operates with a power supply voltage (Vcc) in the range of 4.75V to 5.25V.

It’s important to refer to the datasheet of the specific manufacturer for detailed information on electrical characteristics, timing diagrams, and recommended operating conditions. The 74LS161 is widely available and has been used in a variety of digital electronics projects over the years.

Arcade Games and Pinball Machines that Use 74LS161

Here’s a list of arcade games and pinball machines that use the the 74LS161 on their PCBs.

  • Asteroids
  • Battlezone
  • Centuri
  • Circus Charlie
  • Dig Dug
  • Frogger
  • Gorf
  • Mouse Trap
  • Ms. Pac-Man
  • Outrun
  • Pac-Man
  • Paperboy
  • Pole Postion 1/2
  • Pong
  • Popeye
  • Red Barron
  • Road Blasters
  • Sea Wolf
  • Space Invaders
  • Star Wars
  • Tempest
  • many others…

74LS161 / 74LS161N Pinout

The following represents the pinout of the 74LS161N in a DIP-16 package, commonly used in arcade and pinball machines.

74LS161 Pinout

  • PIN 1: CLEAR
  • PIN 2: CLOCK
  • PIN 3: A Input 1
  • PIN 4: B Input 2
  • PIN 5: C Input 3
  • PIN 6: D Input 4
  • PIN 7: Enable P
  • PIN 8: Ground
  • PIN 9: Load
  • PIN 10: Enable T
  • PIN 11: D Output 4
  • PIN 12: C Output 3
  • PIN 13: B Output 2
  • PIN 14: A Output 1
  • PIN 15: Ripple Carry Output
  • PIN 16: Vcc

74LS161 Datasheet

You can find the datasheet for the 74LS161 here: 74LS161 datasheet

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