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.