## Technical Overview: SN74HCS393DYYR The **SN74HCS393DYYR** is a high-speed CMOS (HCS), dual 4-bit binary counter manufactured by Texas Instruments. It belongs to the HCS logic family, which is specifically designed for automotive and industrial applications requiring noise immunity and high-speed performance. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Logic Family** | HCS (High-Speed CMOS with Schmitt-trigger inputs) | | **Logic Function** | Dual 4-bit Binary Counter | | **Operating Voltage ($V_{CC}$)** | 2.0 V to 6.0 V | | **Input Type** | Schmitt-trigger inputs (allows for slow or noisy signals) | | **Output Current** | ±7.8 mA at 6 V | | **Package Type** | SOT-662 (DYY), 14-pin (Ultra-small) | | **Operating Temperature** | -40°C to 125°C | --- ### 2. Functional Description The device consists of two independent 4-bit binary counters, each with its own Clock ($CP$) and Clear ($CLR$) pins. * **Counting Mechanism:** The counter advances on the high-to-low transition (negative edge) of the clock input. * **Reset Function:** A high level on the $CLR$ line resets the counter to zero ($0000$) asynchronously, regardless of the clock state. * **Cascadability:** Since there are two 4-bit counters in one package, they can be cascaded to form a single 8-bit counter ($2^8 = 256$ states). --- ### 3. Pin Configuration | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | 1CP | Clock Input, Counter 1 (Active Falling Edge) | | 2 | 1CLR | Master Reset, Counter 1 (Active High) | | 3, 4, 5, 6 | 1Q0 - 1Q3 | Parallel Outputs, Counter 1 | | 7 | GND | Ground | | 8, 9, 10, 11 | 2Q3 - 2Q0 | Parallel Outputs, Counter 2 | | 12 | 2CLR | Master Reset, Counter 2 (Active High) | | 13 | 2CP | Clock Input, Counter 2 (Active Falling Edge) | | 14 | $V_{CC}$ | Supply Voltage | --- ### 4. Distinctive Features 1. **Schmitt-Trigger Inputs:** This is the "S" in HCS. It provides hysteresis on all inputs, making the chip highly tolerant of slow signal transitions and noisy environments. It effectively eliminates "chatter" or multiple triggering. 2. **Low Power Consumption:** As a CMOS device, it consumes very little static power, making it ideal for battery-operated devices. 3. **DYY Package:** The "DYYR" suffix indicates a very small SOT package, suitable for space-constrained PCB designs. --- ### 5. Common Applications * **Frequency Division:** Dividing a high-frequency clock down to a lower frequency. * **Digital Timers:** Acting as the counting core for time-keeping circuits. * **Event Counting:** Tracking pulses from sensors or switches. * **Automotive Systems:** Used in infotainment or body control modules due to its robust noise immunity.