The TC74HC4520A is high speed CMOS DUAL BCD/4-BIT BINARY COUNTER fabricated with silicon gate C2MOS technology.

It achieves the high speed operation similar to equivalent LSTTL while maintaining the CMOS low power dissipation. Since it contains two independent counter circuits in one package, counting or frequency division of eight binary bits can be achieved with one device. The counter is reset to “O” (Q0 to Q3 low) by setting the CLR input high regardless of the other inputs. Counting occurs on the positive going (rising edge) transition of CK if CE is high or the negative going (falling edge) transition of CK if CE is low.

All inputs are equipped with protection circuits against static discharge or transient excess voltage.

特性 Features

? High speed: fmax =55 MHz (typ.) at VCC =5 V

? Low power dissipation: ICC =4 μA (max) at Ta =25°C

? High noise immunity: VNIH =VNIL =28 VCC(min)

? Outputs drive capability: 10 LSTTL loads

? Symmetrical output impedance: |IOH| =IOL =4 mA (min)

? Balanced propagation delays: tpLH～ ? tpHL

? Wide operating voltage range: VCC (opr) =2 to 6 V

? Pin and function compatible with TC4520B