## Overview of the SN54162J The **SN54162J** is a high-performance, synchronous 4-bit decade (BCD) counter belonging to the Transistor-Transistor Logic (TTL) family. It is specifically designed for military-grade applications, characterized by the "54" prefix and the "J" suffix (Ceramic Dual-In-Line Package). --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Logic Family** | TTL (Standard) | | **Function** | Synchronous 4-Bit Decade Counter | | **Counting Sequence** | BCD (0 to 9) | | **Supply Voltage ($V_{CC}$)** | 4.5V to 5.5V | | **Operating Temperature** | -55°C to 125°C | | **Package Type** | J (16-pin Ceramic DIP) | | **Clock Frequency ($f_{max}$)** | Typ. 25 MHz | --- ### 2. Functional Characteristics The SN54162J is distinguished by its fully synchronous operation. This means all state changes (counting, loading, and clearing) occur simultaneously with the positive-going edge of the clock pulse. #### Internal Components * **Flip-Flops:** Four master-slave JK flip-flops. * **Gating Logic:** Internal look-ahead circuitry for high-speed counting and carry generation. * **Synchronous Clear:** Unlike the SN54160, the '162 version features a **synchronous clear**. The clear input must be low during a clock transition to reset the counter to zero. #### Pin Configuration (16-Pin DIP) | Pin No. | Name | Description | | :--- | :--- | :--- | | 1 | $\overline{CLR}$ | Synchronous Clear (Active Low) | | 2 | CLK | Clock Input (Positive Edge Triggered) | | 3-6 | A, B, C, D | Data Inputs (for Presetting) | | 7 | ENP | Count Enable Parallel | | 8 | GND | Ground | | 9 | $\overline{LOAD}$ | Synchronous Load (Active Low) | | 10 | ENT | Count Enable Trickle | | 11-14 | $Q_D, Q_C, Q_B, Q_A$ | Data Outputs | | 15 | RCO | Ripple Carry Output | | 16 | $V_{CC}$ | Power Supply | --- ### 3. Operational Logic Table | $\overline{CLR}$ | $\overline{LOAD}$ | ENP | ENT | Action | | :---: | :---: | :---: | :---: | :--- | | L | X | X | X | Reset to 0 (at next Clock $\uparrow$) | | H | L | X | X | Load Data (A,B,C,D) at next Clock $\uparrow$ | | H | H | H | H | Count Up | | H | H | L | X | Hold (No Change) | | H | H | X | L | Hold (No Change, RCO goes Low) | --- ### 4. Comparison: SN54162 vs. SN54160 The primary difference lies in the **Clear** function: * **SN54160:** Asynchronous Clear (Resets immediately regardless of the clock). * **SN54162:** Synchronous Clear (Resets only on the next rising edge of the clock). ---