### M54HC393D Electronic Overview The **M54HC393D** is a high-speed CMOS device consisting of two independent 4-bit binary ripple counters. It is primarily used in digital circuits for frequency division, counting, and timing applications. --- ### 1. Key Technical Specifications Below are the primary electrical characteristics of the M54HC393D: | Parameter | Specification | | :--- | :--- | | **Logic Family** | 54HC (High-speed CMOS) | | **Operating Voltage ($V_{CC}$)** | 2V to 6V | | **Propagation Delay** | ~15ns at 4.5V | | **Operating Temperature** | -55°C to +125°C (Military Grade) | | **Max Clock Frequency** | ~50 MHz at 4.5V | | **Package Type** | SO-14 (D suffix indicates Ceramic/SOIC) | --- ### 2. Functional Description The device contains two identical, independent 4-stage counters. Because it is a **ripple counter**, the output of one flip-flop acts as the clock for the next. #### A. Pin Functions * **1CP, 2CP (Clock Inputs):** Triggered on the high-to-low transition (Negative Edge). * **1CLR, 2CLR (Clear):** Asynchronous high-level inputs that reset all counter stages to zero (0000). * **QA to QD:** The four parallel outputs representing the 4-bit binary count. #### B. Truth Table (Per Counter) | Clock (CP) | Clear (CLR) | Output (QA - QD) | | :---: | :---: | :--- | | X | H | All outputs = Low (0) | | $\downarrow$ | L | Count advances by 1 | | $\uparrow$ | L | No change | --- ### 3. Internal Architecture The chip uses Silicon Gate $C^2MOS$ technology, which allows it to achieve speeds similar to LSTTL while maintaining the low power consumption of CMOS. ```mermaid graph LR CP[Clock Input] --> FF0[Flip-Flop A] FF0 --> QA FF0 --> FF1[Flip-Flop B] FF1 --> QB FF1 --> FF2[Flip-Flop C] FF2 --> QC FF2 --> FF3[Flip-Flop D] FF3 --> QD CLR[Clear Input] -.-> FF0 & FF1 & FF2 & FF3 ``` --- ### 4. Common Applications * **Frequency Dividers:** By using specific outputs, you can divide the input frequency by 2, 4, 8, or 16. * **Long-duration Timers:** By cascading the two counters, a single chip can function as an 8-bit counter (divide by 256). * **Digital Clocks:** Used in the logic stages to track seconds, minutes, or hours. * **Military/Aerospace:** The "M" prefix and wide temperature range make it suitable for harsh environments.