The **U74HC574G-R20-R** is a high-speed CMOS octal D-type flip-flop with 3-state outputs. It is commonly used in digital circuits for data buffering, bus interfacing, and temporary data storage. ### 1. General Specifications The following table summarizes the core technical characteristics of this component: | Parameter | Specification | | :--- | :--- | | **Logic Type** | Octal D-Type Flip-Flop (Positive Edge Triggered) | | **Technology** | High-Speed CMOS (HC) | | **Output Type** | 3-State (Tri-state) | | **Supply Voltage (Vcc)** | 2.0V to 6.0V | | **Number of Bits** | 8-bit | | **Propagation Delay** | ~13ns to 30ns (depending on Vcc) | | **Operating Temperature** | -40°C to +85°C | --- ### 2. Pin Configuration and Functions The device typically features 20 pins. Below is the functional breakdown: 1. **OE (Output Enable):** Active Low. When LOW, data is available at the outputs. When HIGH, outputs are in a high-impedance state (floating). 2. **D0 - D7:** Data inputs for the 8 flip-flops. 3. **CP (Clock Pulse):** Positive edge-triggered. Data at the D inputs is transferred to the Q outputs on the transition from LOW to HIGH. 4. **Q0 - Q7:** 3-state non-inverting outputs. 5. **GND / VCC:** Ground and Power supply pins. --- ### 3. Key Operational Features * **Edge Triggering:** The device captures data only on the rising edge of the clock. This prevents "transparent" behavior where outputs follow inputs directly, ensuring synchronized data transfer. * **3-State Logic:** The ability to set outputs to high-impedance allows multiple devices to share the same bus lines without causing signal contention. * **High Noise Immunity:** As a CMOS device, it offers excellent resistance to electrical noise, making it suitable for industrial environments. * **Low Power Consumption:** Static power consumption is extremely low, typical of HC-series logic. --- ### 4. Part Number Breakdown (UTC Naming Convention) The part number can be decoded as follows: * **U74HC:** Logic family (High-speed CMOS). * **574:** Function code (Octal D-type flip-flop, non-inverting). * **G:** Halogen-free and RoHS compliant. * **R20:** Package code (likely SOP-20 or SSOP-20). * **R:** Tape and Reel packaging. --- ### 5. Application Circuit Example In a typical microcontroller system, the U74HC574 is used as an **Output Port Expander**: ```c // Pseudo-logic for driving the 574 1. Set Data on D0-D7 pins of the MCU. 2. Pulse the CP (Clock) pin from LOW to HIGH. 3. The data is now "latched" and held at Q0-Q7. 4. Set OE to LOW to drive the external peripheral. ``` ---