The **54S162J** is a high-speed, military-grade integrated circuit belonging to the Schottky TTL (Transistor-Transistor Logic) family. It is specifically a **Synchronous 4-Bit Decade Counter**. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Logic Family** | 54S (High-Speed Schottky) | | **Function** | Decade Counter (0-9 BCD) | | **Counting Mode** | Fully Synchronous | | **Package Type** | CERDIP (Ceramic Dual In-Line Package) - "J" Suffix | | **Supply Voltage ($V_{CC}$)** | 4.5V to 5.5V | | **Operating Temperature** | -55°C to 125°C (Military Grade) | | **Typical Clock Frequency** | 40 MHz to 70 MHz | --- ### 2. Functional Description The 54S162J is designed for high-performance counting applications where speed and synchronization are critical. Unlike ripple counters, the flip-flops in this IC are triggered simultaneously by the clock. * **Synchronous Operation:** All state changes (counting, preset, and reset) occur coincident with the positive-going edge of the clock pulse. * **Decade Counting:** It counts from 0000 to 1001 (0 to 9 in decimal) and then resets to 0000. * **Synchronous Reset:** Unlike the 54S160, which has an asynchronous reset, the 54S162 reset is synchronized with the clock. A low level at the clear input sets the outputs to low only after the next clock edge. * **Programmable:** It features parallel load inputs, allowing the counter to be preset to any 4-bit BCD number. --- ### 3. Pinout Overview The device typically comes in a 16-pin configuration. Below is the functional breakdown of the pins: | Pin Type | Name | Description | | :--- | :--- | :--- | | **Inputs** | $P_0, P_1, P_2, P_3$ | Data inputs for parallel loading. | | **Control** | $\overline{SR}$ | Synchronous Reset (Active Low). | | **Control** | $\overline{PE}$ | Parallel Enable (Active Low). | | **Clock** | $CP$ | Clock Pulse (Triggered on rising edge). | | **Enable** | $CEP, CET$ | Count Enable Parallel / Trickle (used for cascading). | | **Outputs** | $Q_0, Q_1, Q_2, Q_3$ | BCD Counter Outputs. | | **Terminal** | $TC$ | Terminal Count (Carry output for cascading). | --- ### 4. Implementation Example To use this in a digital circuit, the following logic levels are generally applied: ```vhdl -- Example Logic Logic for 54S162 -- If Reset = Low: On next Clock, Output = 0000 -- If Load = Low: On next Clock, Output = Parallel Inputs -- If ENP and ENT = High: Count on every Clock edge ```