CD74HC4518 - High Speed CMOS Logic Dual BCD Up-Counter

The CD74HC4518 is a dual BCD up-counter. The ’HC4520 and CD74HCT4520 are dual binary up-counters. Each device consists of two independent internally synchronous 4-stage counters. The counter stages are D-type flip-flops having interchangeable CLOCK and ENABLE lines for incrementing on either the positive-going or the negative-going transition of CLOCK. The counters are cleared by high levels on the MASTER RESET lines. The counter can be cascaded in the ripple mode by connecting Q₃ to the ENABLE input of the subsequent counter while the CLOCK input of the latter is held low.

• Positive or Negative Edge Triggering
• Synchronous Internal Carry Propagation
• Fanout (Over Temperature Range)
  • Standard Outputs...10 LSTTL Loads
  • Bus Driver Outputs...15 LSTTL Loads
• Wide Operating Temperature Range... –55°C to 125°C
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL Logic ICs
• HC Types
  • 2V to 6V Operation
  • High Noise Immunity: N_IL = 30%, N_IH = 30% of V_CC at V_CC = 5V
• HCT Types
  • 4.5V to 5.5V Operation
  • Direct LSTTL Input Logic Compatibility, V_IL = 0.8V (Max), V_IH = 2V (Min)
  • CMOS Input Compatibility, I_l 1µA at V_OL, V_OH