MM74C928

Features:

 Wide supply voltage range: 3V to 6V
 Guaranteed noise margin: 1V
 High noise immunity: 0.45 V_CC (typ.)
 High segment sourcing current: 40 mA @ V_CC - 1.6V, V_CC = 5V
 Internal multiplexing circuitry


Specifications

Voltage at Any Output Pin                               GND - 0.3V to V_CC + 0.3V
Voltage at Any Input Pin                                          GND - 0.3V to +15V
Operating Temperature
Range (T_A)                                                                    -40°C to +85°C
Storage Temperature
Range                                                                        -65°C to +150°C
Power Dissipation (P_D)                           Refer to P_D(MAX) vs T_A Graph
Operating V_CC Range                                                             3V to 6V
V_CC                                                                                               6.5V
Lead Temperature
(Soldering, 10 seconds)                                                           260°C


Description

   The MM74C925, MM74C926, MM74C927 and MM74C928 CMOS counters 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 has its own free-running oscillator, and requires no external clock. The counters advance on negative edge of clock. A HIGH signal of MM74C911 on the Reset input will reset the counter to zero, and reset the carry-out LOW. A LOW signal on the Latch Enable input will latch the number in the counters into the internal output latches. A HIGH signal on Display Select input will select the number in the counter to be displayed; a LOW level signal on the Display Select will select the number in the output latch to be displayed.

   The MM74C925 is a 4-decade counter and has Latch Enable, Clock and Reset inputs.

   The MM74C926 is like the MM74C925 except that it has a display select and a carry-out used for cascading counters. The carry-out signal goes HIGH at 6000, goes back LOW at 0000.

   The MM74C927 is like the MM74C926 except the second most significant digit divides by 6 rather than 10. Thus, if the clock input frequency is 10 Hz, the display would read tenths of seconds and minutes (i.e., 9:59.9).

   The MM74C928 is like the MM74C926 except the most significant digit divides by 2 rather than 10 and the carry-out is an overflow indicator which is HIGH at 2000, and it goes back LOW only when the counter is reset. Thus, this is a 3½-digit counter.