●The CD74HC390 and HCT390 dual 4-bit decade ripple counters are high-speed silicon-gate CMOS devices and are pin compatible with low-power Schottky TTL (LSTTL). These devices are divided into four separately clocked sections. The counters have two divide-by-2 sections and two divide-by-5 sections. These sections are normally used in a BCD decade or bi quinary configuration, since they share a common master reset (nMR). If the two master reset inputs (1MR and 2MR) are used to simultaneously clear all 8 bits of the counter, a number of counting configurations are possible within one package. The separate clock inputs (nCP0\ and nCP1\\) of each section allow ripple counter or frequency division applications of divide-by-2, 4. 5, 10, 20, 25, 50 or 100. Each section is triggered by the High-to-Low transition of the input pulses (nCP0\ and nCP1\\).
●For BCD decade operation, the nQ0 output is connected to the nCP1\ input of the divide-by-5 section. For bi-quinary decade operation, the nO3 output is connected to the nCP0\ input and nQ0 becomes the decade output.
●The master reset inputs (1MR and 2MR) are active-High asynchronous inputs to each decade counter which operates on the portion of the counter identified by the "1" and "2" prefixes in the pin configuration. A High level on the nMR input overrides the clock and sets the four outputs Low.
● Two BCD Decade or Bi-Quinary Counters
● One Package Can Be Configured to Divide-by-2, 4, 5,10, 20, 25, 50 or 100
● Two Master 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
●\- 4.5V to 5.5V Operation
●\- Direct LSTTL Input Logic Compatibility, VIL = 0.8V (Max), VIH = 2V (Min)
●\- CMOS Input Compatibility, Il 1µA at VOL, VOH
●Data sheet acquired from Harris Semiconductor
