## Overview of SN74HC393DRE4 The **SN74HC393DRE4** is a high-speed CMOS device manufactured by Texas Instruments. It contains **two independent 4-bit binary counters** (dual 4-stage ripple counters) in a single package. It is widely used for frequency division, timekeeping, and digital counting applications. --- ### 1. Key Technical Specifications | Parameter | Value / Description | | :--- | :--- | | **Logic Family** | HC (High-Speed CMOS) | | **Function** | Dual 4-Bit Binary Counter | | **Operating Voltage (Vcc)** | 2.0V to 6.0V | | **Package Type** | SOIC-14 (Small Outline Integrated Circuit) | | **Max Frequency (at 6V)** | ~36 MHz | | **Propagation Delay** | ~13 ns (at 6V) | | **Operating Temperature** | -40°C to +85°C | | **Output Current** | ±5.2 mA | --- ### 2. Internal Architecture and Pinout The device consists of two separate sections (A and B). Each section has: * **Clock Input ($\overline{CP}$):** Triggered on the High-to-Low transition (falling edge). * **Master Reset (MR):** An active-high input that clears all flip-flops to zero. * **Outputs ($Q_0, Q_1, Q_2, Q_3$):** Provide the 4-bit binary count. #### Pin Configuration Table | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | 1CP | Clock Input, Counter 1 | | 2 | 1MR | Master Reset, Counter 1 | | 3, 4, 5, 6 | 1Q0 - 1Q3 | Parallel Outputs, Counter 1 | | 7 | GND | Ground (0V) | | 8, 9, 10, 11| 2Q3 - 2Q0 | Parallel Outputs, Counter 2 | | 12 | 2MR | Master Reset, Counter 2 | | 13 | 2CP | Clock Input, Counter 2 | | 14 | Vcc | Supply Voltage | --- ### 3. Functional Logic The SN74HC393DRE4 functions as a **ripple counter**. In a ripple counter, the output of one flip-flop acts as the clock for the next. * **Counting Sequence:** It increments on every falling edge of the clock signal. * **Cascading:** Since it is a dual counter, you can connect the $Q_3$ of the first counter to the $CP$ of the second counter to create an **8-bit binary counter** (counting from 0 to 255). * **Resetting:** Applying a HIGH signal to the MR pin overrides the clock and forces all outputs to LOW immediately. --- ### 4. Typical Applications 1. **Frequency Dividers:** By using specific outputs ($Q_0$ = divide by 2, $Q_1$ = divide by 4, etc.). 2. **Digital Clocks:** Counting pulses from an oscillator to track seconds, minutes, or hours. 3. **Delay Generators:** Creating specific timing intervals in logic circuits. 4. **Event Counting:** Tracking the number of pulses generated by a sensor. ---