1 Features

• Fully static operation

• Buffered inputs

• Common reset

• Negative edge clocking

• Fanout (over temperature range)

– Standard outputs: 10 LSTTL loads

– Bus driver outputs: 15 LSTTL loads

• Wide operating temperature range: -55℃ to 125℃

• Balanced propagation delay and transition times

• Significant power reduction compared to LSTTL

Logic ICs

• HC types

– 2 V to 6 V operation

– High noise immunity: NIL = 30%, NIH = 30% of

VCC at VCC = 5 V

• HCT types

– 4.5 V to 5.5 V operation

– Direct LSTTL input logic compatibility, VIL = 0.8

V (max), VIH = 2 V (min)

– CMOS input compatibility, II ≤ 1 μA at VOL,VOH

2 Description

The ’HC4020 and ’HCT4020 are 14-stage ripple-carry

binary counters. All counter stages are controller/

peripheral flip- flops. The state of the stage advances

one count on the negative clock transition of each

input pulse; a high voltage level on the MR line resets

all counters to their zero state. All inputs and outputs

are buffered.