The **74HC393D,652** is a high-speed CMOS device featuring two independent 4-bit binary counters (dual 4-stage ripple counters). It is widely used in digital circuits for frequency division, timing, and counting applications. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Logic Family** | HC (High-speed CMOS) | | **Function** | Dual 4-Bit Binary Ripple Counter | | **Voltage Supply (Vcc)** | 2.0V to 6.0V | | **Output Current** | ±5.2 mA | | **Max Frequency (fmax)** | 79 MHz (at 6V), 27 MHz (at 2V) | | **Package Type** | SOIC-14 (Small Outline IC) | | **Operating Temperature** | -40°C to +125°C | | **Mounting Type** | Surface Mount (SMD/SMT) | --- ### 2. Internal Structure and Pinout The chip contains two identical, independent counter sections. Each section has a **Clock Input ($\overline{CP}$)** and a **Master Reset (MR)**. * **Clock Input ($\overline{CP}$):** Triggered on the High-to-Low transition (falling edge). * **Master Reset (MR):** Active-High. When MR is high, it overrides the clock and resets all four bits of that counter to zero ($Q0-Q3 = Low$). * **Outputs ($Q0, Q1, Q2, Q3$):** These represent the binary count ($2^0$ to $2^3$). ### 3. Logic Operation Because it is a **ripple counter**, the output of the first flip-flop serves as the clock for the second, and so on. This creates a slight delay (ripple) between stages, but simplifies the internal circuitry. #### Binary Counting Sequence (Per Section): | Clock Pulse | Q3 | Q2 | Q1 | Q0 | Decimal | | :--- | :---: | :---: | :---: | :---: | :---: | | Reset | 0 | 0 | 0 | 0 | 0 | | 1st Fall | 0 | 0 | 0 | 1 | 1 | | 2nd Fall | 0 | 0 | 1 | 0 | 2 | | ... | ... | ... | ... | ... | ... | | 15th Fall | 1 | 1 | 1 | 1 | 15 | --- ### 4. Part Number Breakdown (74HC393D,652) The suffix provides information about the packaging and distribution: * **74HC:** High-speed CMOS logic family. * **393:** Function identifier (Dual 4-bit binary counter). * **D:** Package code for SOIC (Small Outline Integrated Circuit). * **652:** Specific Nexperia/NXP code indicating the device is shipped in **Standard Rail/Tube** packaging (as opposed to Tape & Reel). ### 5. Common Applications * **Frequency Dividers:** Dividing a high-frequency clock down to lower frequencies (e.g., $1/2, 1/4, 1/16$). * **Time Delay Generation:** Creating specific intervals in digital logic. * **Long-period Timers:** By cascading the two counters, you can create an 8-bit ripple counter ($256$ states). ---