1 Features

• Two BCD decade or bi-quinary counters

• One package can be configured to divide-by-2, 4,

5, 10, 20, 25, 50, 100

• Two controller reset inputs to clear each decade

counter individually

• 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: NIL = 30%, NIH = 30% of

VCC at VCC = 5V

• 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 SN74HC390 and ‘HCT390 devices include two

independent 4-bit decade ripple counters, falling-edge

clocked with asynchronous clear. Each counter is

divided into two sections, a divide-by-2 and divideby-

5 counter, each of which has an independent clock

input. This allows for very flexible configuration of the

device.