CMOS QUAD CHANNEL UART (QUART) The **XR82C684J** is a **Universal Asynchronous Receiver/Transmitter (UART)** manufactured by **EXAR Corporation**.  

### **Key Specifications:**  
- **Interface Type:** Asynchronous Serial (UART)  
- **Data Rate:** Up to **1 Mbps**  
- **FIFO Buffers:** **64-byte** transmit and receive FIFOs  
- **Operating Voltage:** **5V**  
- **Package:** **PLCC-44** (Plastic Leaded Chip Carrier)  
- **Operating Temperature Range:** **Commercial (0°C to +70°C)**  

### **Features:**  
- **Full-duplex** operation  
- **Programmable** baud rate generator  
- **Auto-hardware/software flow control** (RTS/CTS, XON/XOFF)  
- **Modem control signals** (DTR, DSR, RTS, CTS, RI, CD)  
- **Independent** transmit and receive clock inputs  
- **Software-selectable** baud rates  
- **Compatible** with industry-standard **16C450/16C550** UARTs  
- **Low-power** CMOS technology  

### **Applications:**  
- **Serial communications** in embedded systems  
- **Industrial control** systems  
- **Point-of-sale (POS)** terminals  
- **Networking equipment**  

This UART is designed for high-performance serial data communication with enhanced buffering and flow control capabilities.  

(Source: EXAR Corporation datasheets and product documentation.)