## SN74ALVCH16823DGGR Technical Overview The **SN74ALVCH16823DGGR** is a high-performance, 18-bit edge-triggered D-type flip-flop manufactured by Texas Instruments. It is designed specifically for low-voltage (1.65V to 3.6V) operation and features **bus-hold** circuitry, making it ideal for high-speed data buffering in modern computing and networking hardware. --- ### Core Specifications | Parameter | Specification | | :--- | :--- | | **Logic Type** | 18-Bit Edge-Triggered D-Type Flip-Flop | | **Supply Voltage (Vcc)** | 1.65 V to 3.6 V | | **Output Current** | 24 mA (High/Low) | | **Max Propagation Delay** | 4.5 ns @ 3.3V | | **Package Type** | TSSOP-56 (Thin Shrink Small Outline Package) | | **Operating Temperature** | -40°C to +85°C | | **Logic Family** | ALVCH (Advanced Low Voltage CMOS with Bus Hold) | --- ### Key Functional Features 1. **18-Bit Architecture**: The device is organized as two separate 9-bit flip-flops. This provides flexibility, allowing it to act as a single 18-bit bus or two independent 9-bit buses. 2. **Bus-Hold Feature**: The "H" in ALVC**H** indicates the inclusion of bus-hold circuitry. This feature holds the last known state of the input when the driving source goes high-impedance (tri-stated). * **Benefit**: Eliminates the need for external pull-up or pull-down resistors on unused or floating inputs, saving board space and power. 3. **3-State Outputs**: The outputs can be put into a high-impedance state via the Output-Enable ($\overline{OE}$) pin, allowing the device to interface directly with bus-organized systems. 4. **Control Inputs**: * **Clock Enable ($\overline{CE}$)**: When high, the clock is ignored, and the data is latched. * **Clear ($\overline{CLR}$)**: An asynchronous input that resets all flip-flops to a low state regardless of the clock. --- ### Pin Configuration Categories | Group | Function | Description | | :--- | :--- | :--- | | **1D - 18D** | Data Inputs | Information at these inputs is transferred to outputs on the clock edge. | | **1Q - 18Q** | Data Outputs | The registered output of the flip-flops. | | **CLK** | Clock Inputs | Triggers the data transfer on the positive-going edge. | | **$\overline{OE}$** | Output Enable | Controls whether the outputs are active or in High-Z state. | | **$\overline{CLR}$** | Clear | Resets the internal registers to zero. | --- ### Typical Applications * **Memory Buffering**: Interfacing between CPUs and SDRAM or Flash memory. * **Signal Level Shifting**: Bridging different voltage domains in mixed-signal systems. * **High-Speed Backplanes**: Used in servers and telecommunication switches for data synchronization.