CD74HCT390MTE4 [Texas Instruments]

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). 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 nQ3 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.