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.
Data sheet acquired from Harris Semiconductor
|Part number||Order||Technology Family||VCC (Min) (V)||VCC (Max) (V)||Bits (#)||Voltage (Nom) (V)||F @ nom voltage (Max) (MHz)||ICC @ nom voltage (Max) (mA)||tpd @ nom Voltage (Max) (ns)||IOL (Max) (mA)||IOH (Max) (mA)||Function||Type||Rating||Operating temperature range (C)||Package Group|
|28||0.08||52||5.2||-5.2||Counter||Decade||Catalog||-55 to 125||
PDIP | 16
SOIC | 16