IC Chips - 4520

4520
Dual 4-bit synchronous binary counter
PDF datasheet

Pin	Symbol	Description
1	1CP0	counter 1 clock input (low-to-high triggered)
2	1CP 1	counter 1 clock input (high-to-low triggered)
3	1Q0	counter 1 output
4	1Q1	counter 1 output
5	1Q2	counter 1 output
6	1Q3	counter 1 output
7	1MR	counter 1 master reset (active high)
8	GND	ground
9	2CP0	counter 2 clock input (low-to-high triggered)
10	2CP 1	counter 2 clock input (high-to-low triggered)
11	2Q0	counter 2 output
12	2Q1	counter 2 output
13	2Q2	counter 2 output
14	2Q3	counter 2 output
15	2MR	counter 2 master reset (active high)
16	Vcc	supply voltage

Notes
The 4520 counts from 0 to 15. The 4518 is identical but counts from 0 to 9. Either nCP0 or nCP 1 may be used as the clock input; the other can be used as a clock enable input. If nCP 1 is high, the counter advances on a low-to-high transition of nCP0. If nCP0 is low, the counter advances on a high-to-low transition of nCP 1.