74HC/HCT390

General description

The 74HC/HCT390 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.

The 74HC/HCT390 are dual 4-bit decade ripple counters 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 input (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 clocks (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 clock inputs (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 clocks and sets the four outputs LOW.

Features

• 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
• Output capability: standard
• I_CC category: MSI

Products/packages

Quality/reliability/chemical content

Quality and reliability disclaimer

Pricing/ordering/availability

Applications

• Automotive systems
• 12 V, 24 V and 42 V loads
• Motors, lamps and solenoids
• General purpose power switching.

Design support

Support Documents

HCT_USER_GUIDE; HC/T User Guide (1997-11-01)

Parametrics/similar products

Similar products
74HC/HCT390 links to the similar products page containing an overview of products that are similar in function or related to the type number(s) as listed on this page. The similar products page includes products from the same catalog tree(s), relevant selection guides and products from the same functional category.

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Disclaimers

• General product disclaimer
• Quality and reliability disclaimer