## Technical Overview: DM54LS374J The **DM54LS374J** is a high-performance, Octal D-type edge-triggered flip-flop with 3-state outputs. It belongs to the **Low-power Schottky (LS)** family of TTL (Transistor-Transistor Logic) integrated circuits. This specific part is designed for military-grade applications, as indicated by the "54" prefix (as opposed to the "74" commercial series). --- ### Core Functional Specifications The device consists of eight edge-triggered D-type flip-flops. On the positive transition of the clock (CP), the $Q$ outputs are set to the logic levels that were set up at the $D$ inputs. | Parameter | Specification | | :--- | :--- | | **Logic Family** | LS-TTL (Low-power Schottky) | | **Function** | Octal D-Type Flip-Flop | | **Triggering** | Positive Edge-Triggered | | **Output Type** | 3-State (Tri-state) | | **Voltage Supply ($V_{CC}$)** | 4.5V to 5.5V | | **Operating Temperature** | -55°C to +125°C (Military Grade) | | **Package Type** | J (Ceramic Dual-In-Line / CERDIP) | --- ### Pin Configuration & Descriptions The DM54LS374J typically comes in a 20-pin package. | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **OE** | Output Enable (Active Low) | | 2, 5, 6, 9, 12, 15, 16, 19 | **Q0 - Q7** | 3-State Outputs | | 3, 4, 7, 8, 13, 14, 17, 18 | **D0 - D7** | Data Inputs | | 11 | **CP** | Clock Pulse Input (Positive Edge) | | 10 | **GND** | Ground | | 20 | **Vcc** | Power Supply | --- ### Key Features 1. **3-State Outputs:** Designed specifically for driving bus lines or interfacing with microprocessors. When the Output Enable ($\overline{OE}$) is HIGH, the outputs are in a high-impedance state (floating). 2. **Hysteresis at Inputs:** The inputs typically feature hysteresis to improve noise immunity. 3. **Low Power Consumption:** The Schottky-clamped circuitry provides high speed (typical propagation delay of 15-20ns) while maintaining lower power than standard TTL. 4. **Military Robustness:** The "J" suffix indicates a ceramic package, which provides superior thermal management and protection against moisture compared to plastic (N) packages. --- ### Truth Table | $\overline{OE}$ | CP | D | Output Q | | :---: | :---: | :---: | :---: | | L | $\uparrow$ | H | H | | L | $\uparrow$ | L | L | | L | L/H/$\downarrow$ | X | $Q_0$ (No change) | | H | X | X | High Impedance (Z) | --- ### Sample Application Circuit (Conceptual) ```vhdl -- Digital Logic Representation -- When Clock (CP) goes from 0 to 1: -- Q1 <= D1; -- Q2 <= D2; -- ... -- Q8 <= D8; -- All this happens only if OE is tied to Ground (Low). ```