Diodes Incorporated
Back to UART - Universal Asynchronous Receiver / Transmitter


16C550 Quad UART Bridge Controller

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The PI7C9X754 (754), is a 1.62V to 3.6V quad Universal Asynchronous Receiver and Transmitter (UART) with 5V tolerant serial (modem) inputs. The highly integrated device is designed for high bandwidth requirement in communication systems. Each UART has its own 16C550 compatible set of configuration registers, TX and RX FIFOs of 64 bytes, fully programmable transmit and receive FIFO trigger levels, TX and RX FIFO level counters, automatic RTS/CTS hardware flow control with programmable hysteresis, automatic software (Xon/Xoff) flow control, RS-485 half-duplex direction control, Intel or Motorola bus interface and sleep mode for power saving.


  • 1.62V to 3.6V with 5V Tolerant Serial Inputs
  • Programmable Sleep Mode with automatic wake-up
         - Intel or Motorola Data Bus Interface select
  • Each UART is independently controlled with:
         - 6C550 Compatible Register Set
         - 64-byte Transmit and Receive FIFOs
         - Transmit and Receive FIFO Level Counters
         - Programmable TX and RX FIFO Trigger Levels for DMA and Interrupt Generation
             → Programmable Receive FIFO Trigger Levels for Software/Hardware Flow Control
             → Programmable hysteresis(Table A-D) for Software/ Hardware Flow Control
         - Automatic RTS/CTS Flow Control
         - Automatic Xon/Xoff Software Flow Control with Optional Data Flow Resume by Xon Any Character
            → DMA Signaling Capability for both Received and Transmitted Data
         - RS485 HDX Control Output
         - RS485 auto address detection
         - Infrared (IrDA 1.0/1.1) Data Encoder/Decoder
         - Programmable Data Rate with Prescaler
  • Up to 16 Mbps Serial Data Rate with 64MHz external clock input
  • Crystal oscillator(up to 24MHz) or external clock(up to 80MHz) input
  • Built in Power-On-Reset circuit


  • Remote Access Servers
  • Ethernet Network to Serial Ports
  • Network Management
  • Factory Automation and Process Control
  • Point-of-Sale Systems
  • Multi-port RS-232/RS-422/RS-485 Cards

Product Specifications

Product Parameters

Ports 8 UART
Pins 48,64,80,100
Data Rate (kbps) 20Mbps
Bytes 64
Tx/Rx FIFO Ctrs Yes
Tx/Rx FIFO INT Trig Yes
Auto RTS/CTS Yes
Interface 8-Bits
Ambient or Junction Temperature (°C) -40 to 85

Technical Documents

Recommended Soldering Techniques


Additional Technical Documents are available upon request:
Application information, Evaluation board, and Other technical documents

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2567 2022-03-30 2022-09-30 Device End of Life (EOL)
PCN-2328 2018-04-12 2018-10-12 Device End of Life for tray packaging only