## SN74LS393DG4: Dual 4-Bit Binary Counter The **SN74LS393DG4** is a high-speed, Low-power Schottky (LS) CMOS integrated circuit. It contains two independent 4-bit binary counters (ripple clock) in a single package. --- ### 1. Key Specifications | Parameter | Value | | :--- | :--- | | **Logic Family** | LS-TTL (Low-power Schottky) | | **Function** | Dual 4-Bit Binary Counter | | **Counter Type** | Ripple Counter | | **Voltage Supply (Vcc)** | 4.75V to 5.25V (Standard 5V) | | **Operating Temperature** | 0°C to 70°C | | **Package Type** | SOIC-14 (Small Outline IC) | | **Mounting Type** | Surface Mount | | **Output Current** | 8mA (High-level), -0.4mA (Low-level) | --- ### 2. Functional Description The device consists of two independent 4-stage binary counters. Because it is a **ripple counter**, each bit toggles based on the transition of the previous bit. * **Clock Inputs ($\overline{CP}$):** The counters are triggered by a **High-to-Low** (negative-edge) transition of the clock input. * **Clear Inputs (MR):** Each counter has an independent Master Reset (MR). When MR is set **High**, all four bits of that counter are reset to logic level **0** (Low), overriding the clock. * **Counting Sequence:** It follows a standard binary count from 0 to 15 ($2^4 - 1$). By cascading the two 4-bit sections, the chip can function as an 8-bit counter (counting up to 255). --- ### 3. Pin Configuration (SOIC-14) | Pin Number | Symbol | Function | | :--- | :--- | :--- | | 1 | 1CP | Clock Input, Counter 1 (Active Falling Edge) | | 2 | 1MR | Master Reset, Counter 1 (Active High) | | 3, 4, 5, 6 | 1Q0 - 1Q3 | Outputs, Counter 1 | | 7 | GND | Ground (0V) | | 8, 9, 10, 11| 2Q3 - 2Q0 | Outputs, Counter 2 | | 12 | 2MR | Master Reset, Counter 2 (Active High) | | 13 | 2CP | Clock Input, Counter 2 (Active Falling Edge) | | 14 | Vcc | Positive Supply Voltage (+5V) | --- ### 4. Logic Table (Per Counter) | Reset (MR) | Clock ($\overline{CP}$) | Output State | | :--- | :--- | :--- | | H | X | All Outputs Low (L) | | L | $\downarrow$ | Count Up | | L | H or L | No Change | --- ### 5. Common Applications * **Frequency Dividers:** By using the Q outputs, the input clock frequency can be divided by 2, 4, 8, or 16. * **Time Delay Generation:** Creating specific intervals in digital circuits. * **Address Accumulators:** Used in older CPU architectures or memory indexing. * **Digital Clocks:** Serving as the base for seconds/minutes counting logic. ---