The MM74C925, MM74C926, MM74C927, and MM74C928 are 4-digit counters with multiplexed 7-segment output drivers. They are CMOS counters that have an internal output latch, NPN output sourcing drivers for a 7-segment display, and internal multiplexing circuitry. The counters advance on the negative edge of the clock and can be reset to zero using the reset input. The latch enable input allows for latching the numbers in the counters into the internal output latches. The display select input determines which number is displayed. The MM74C925 is a 4-decade counter with latch enable, clock, and reset inputs. The MM74C926 is similar to the MM74C925, but it also has a display select input and a carry-out output for cascading counters. The carry-out signal goes high at 6000 and goes back low at 0000. The MM74C927 is similar to the MM74C926, but the second most significant digit divides by 6 instead of 10.
The MM74C925, MM74C926, MM74C927, and MM74C928 are CMOS counters that consist of a 4-digit counter, an internal output latch, NPN output sourcing drivers for a 7-segment display, and an internal multiplexing circuitry with four multiplexing outputs. The multiplexing circuit includes a free-running oscillator, requiring no external clock, and the counters advance on the negative edge of the clock signal.
| Supply Voltage Range | 3V to 6V |
|---|---|
| Operating Temperature Range | -40°C to +85°C |
| Maximum Segment Sourcing Current | 40 mA |
| Input Protection Voltage | 15V |
No, the internal multiplexing circuit has its own free-running oscillator and requires no external clock.
A HIGH signal on the Reset input will reset the counter to zero and reset the carry-out LOW.
A HIGH signal selects the number in the counter to be displayed, while a LOW level signal selects the number in the output latch.