The **U74ACT240G-P20-R** is a high-speed CMOS octal buffer/line driver with 3-state outputs, designed primarily for high-performance bus-oriented applications. Below is a detailed breakdown of its technical specifications and functional characteristics. --- ## 1. Technical Overview The "74ACT" family indicates that this part is an Advanced CMOS device with TTL-compatible inputs. The "240" logic function specifically refers to an **inverting** buffer. ### Key Specifications | Parameter | Specification | | :--- | :--- | | **Logic Function** | Octal Inverting Buffer/Line Driver | | **Output Type** | 3-State (Tri-state) | | **Operating Voltage ($V_{CC}$)** | 4.5V to 5.5V | | **Input Type** | TTL-Compatible | | **Propagation Delay** | ~5ns to 8ns (High Speed) | | **Operating Temperature** | -40°C to +85°C | | **Package Type** | TSSOP-20 (P20) | --- ## 2. Functional Description The device consists of eight independent inverting buffers organized into two groups of four. Each group is controlled by an Output Enable ($\overline{OE}$) pin. * **Inverting Logic:** If the input is HIGH, the output is LOW (and vice versa). * **3-State Outputs:** When the $\overline{OE}$ pin is HIGH, the outputs are placed in a high-impedance state (Hi-Z), effectively disconnecting them from the bus. * **Drive Capability:** These chips are designed to drive large capacitive loads (like backplanes or long PCB traces) without significant signal degradation. ### Truth Table For each gate: | Inputs $\overline{OE}$ | Input A | Output Y | | :---: | :---: | :---: | | L | L | H | | L | H | L | | H | X | Z (High Impedance) | --- ## 3. Part Number Breakdown The suffix and prefix provide information about the manufacturer's specific packaging and delivery: * **U74:** Typically indicates the manufacturer (Unisonic Technologies - UTC). * **ACT:** Advanced CMOS with TTL-compatible inputs. * **240:** Inverting Octal Buffer logic code. * **G:** Halogen-free and RoHS compliant. * **P20:** TSSOP-20 Package. * **R:** Tape & Reel (Packaging method). --- ## 4. Typical Applications * **Memory Address Drivers:** Interfacing microprocessors with memory modules. * **Bus Transceivers:** Managing data flow on a shared data bus. * **Clock Distribution:** Providing clean, inverted clock signals to multiple components. * **Level Shifting:** Interfacing 3.3V logic (as inputs) to 5V systems.