5-Decade Counter with Multiplexed Output

In the article 5-Decade Counter with Multiplexed Output we will discuss about decade counter it’s key parameter and its applications. Let’s start with description.

5-Decade Counter with Multiplexed Output Description

This IC is an example of a specific system function implementation. As illustrated in figure 1, the IC contains five-decade counters in cascade. In effect, then, the first counter, 10⁰, will count from 0through 9, the second counter 10¹, will count from 10 to 90, and so on. The total maximum count of this unit is 99,999. The output of the five-decade counters go to the multiplex (MUX) and control section which also receives the scan clock and scan reset input. A binary-coded decimal (BCD) output is available at Q1 through Q4, controlled by the tri-state BCD control level.

The MUX-OUT section indicates which of the five BCD digits appears at any instant at Q1 through Q4. In other words, if a series of five separate decimal displays were used here, such as the visual display of a multimeter, the digit select would enable the 1s, 10s, 100s, etc., in sequence, at Q1 through Q4. A single BCD 7-segment converter and display driver is then connected to all five numerical displays in parallel. The MUX-OUT, controlled by the tri-state digit control signal, then selects, in sequence, each of the five numerical display to be illuminated.

Key Parameters of 5-Decade Counter with Multiplexed Output

The electrical characteristics are the same as for the particular digital IC family.

1. Maximum clock pulse frequency: For CMOS devices, 0.5 to 1.2 MHz.
2. Minimum clock pulse width: 375 to 1,000 ns is minimum for CMOS devices.
3. Master reset pulse width: 450 to 2,000 ns is minimum for CMOS ICs.

Applications

This IC was specifically intended for applications in real time or event counters where frequent updating is required and where multiplexed displays are used.

Representative Part Number: Motorola MC14534

Comments:

The 5-decade counter with MUX output is a special purpose IC and illustrates how counters, in general, can be used as small systems.