MC14518B, MC14520B Dual Up Counters The MC14518B dual BCD counter and the MC14520B dual binary counter are constructed with MOS P channel and N channel enhancement mode devices in a single monolithic structure. Each consists of two identical, independent, internally synchronous 4stage counters. The counter stages are type D flipflops, with interchangeable MC14518B, MC14520B PIN ASSIGNMENT C 1 16 V A DD E 2 15 R A B Q0 3 14 Q3 A B Q1 4 13 Q2 A B Q2 5 12 Q1 A B Q3 6 11 Q0 A B R 7 10 E A B V 8 9 C SS B BLOCK DIAGRAM CLOCK Q0 3 1 Q1 4 C 2 Q2 5 ENABLE Q3 6 R 7 CLOCK 11 Q0 9 12 Q1 C 10 13 Q2 ENABLE 14 Q3 R 15 V = PIN 16 DD V = PIN 8 SS TRUTH TABLE Clock Enable Reset Action 1 0 Increment Counter 0 0 Increment Counter X 0 No Change X 0 No Change 0 0 No Change 1 0 No Change X X 1 Q0 thru Q3 = 0 X = Dont Care