The part number **-244A-R** is typically a suffix or a specific identifier for electronic components, most commonly associated with **logic gates** (specifically the 74HC244 series) or **surface mount resistors/oscillators**. However, in the context of standard industry nomenclature, "244" is most famously linked to the **Octal Buffer/Line Driver**. --- ### 1. Primary Identification: 74HC244A-R The "244A" usually refers to an **Octal Buffer and Line Driver with 3-State Outputs**. These are essential for managing data flow between different sections of a digital circuit. #### Technical Specifications | Feature | Description | | :--- | :--- | | **Type** | Octal Buffer / Line Driver | | **Output Type** | 3-State (High, Low, or High-Impedance) | | **Logic Family** | High-Speed CMOS (HC / HCT / VHC) | | **Channels** | 8-bit (split into two 4-bit sections) | | **Operating Voltage** | Typically 2.0V to 6.0V | | **Suffix "-R"** | Usually denotes **Tape & Reel** packaging or **RoHS Compliant** | --- ### 2. Key Functions of the 244A * **Isolation:** It isolates the input side from the output side, preventing noise or back-EMF from damaging sensitive controllers (like an Arduino or STM32). * **Current Boosting:** It acts as a "driver," taking a weak logic signal and providing enough current to drive multiple LEDs, long cables, or other bus components. * **Bus Management:** The 3-state output allows multiple devices to share the same data line. When the "Output Enable" (OE) pin is high, the chip effectively "disconnects" from the bus. --- ### 3. Pinout Configuration (Standard 20-Pin Package) The "244A" is generally organized into two sets of four buffers. | Pin Number | Function | Description | | :--- | :--- | :--- | | **1, 19** | $\overline{OE}$ | Output Enable (Active Low) | | **2, 4, 6, 8** | $1A_n$ | Inputs for Group 1 | | **3, 5, 7, 9** | $2Y_n$ | Outputs for Group 2 | | **11, 13, 15, 17** | $2A_n$ | Inputs for Group 2 | | **12, 14, 16, 18** | $1Y_n$ | Outputs for Group 1 | | **10** | GND | Ground | | **20** | VCC | Power Supply | --- ### 4. Meaning of the Suffixes * **A**: Usually indicates a revision or a specific version of the CMOS technology (e.g., "Advanced" or "Automotive" grade depending on the manufacturer like Toshiba or ON Semi). * **-R**: * **Packaging:** Most common meaning is **Tape and Reel**, used for automated pick-and-place assembly. * **Environmental:** In some brands (like Rohm), it signifies **RoHS Compliance**. --- ### Common Applications 1. **Memory Address Drivers:** Strengthening signals from a CPU to multiple RAM chips. 2. **Display Drivers:** Driving segments of an LED matrix. 3. **Level Shifting:** Interfacing between different voltage domains (in some specific logic families).