Features and Benefits

  • Bridges an SPI/MICROWIRE or I2C Microprocessor Bus to an Asynchronous Interface Such as RS-485, RS-232, or IrDASM
    • SIR- and MIR-Compliant IrDA Encoder/Decoder
    • Line Noise Indication Ensures Data Link Integrity
  • Deep, 128-Word Buffer and Automated Control Features Help Offload Activity on the Microcontroller
    • Automatic Active-Low RTS_ and Active-Low CTS_ Flow Control
    • Automatic XON/XOFF Software Flow Control
    • 9-Bit Multidrop-Mode Data Filtering
      • Special Character Detection
      • GPIO-Based Character Detection
      • Two Timers Routed to GPIOs
      • 8 Flexible GPIOs with 20mA Drive Capability
  • Saves Board Space
    • TQFN (5mm x 5mm) Package
    • Dual UART in a Single Package
  • Fast Data Rates Allow Maximum System Flexibility Across Interface Standards
    • 24Mbps (max) Data Rate
    • High-Resolution Programmable Baud-Rate
    • SPI Up to 26MHz Clock Rate
    • Fast Mode Plus I2C Up to 1MHz
  • Integrated PLL and Divider
  • Power Management Control Features Minimize Power Consumption for Portable Applications
    • 1.71V to 3.6V Supply Range
    • Shutdown and Autosleep Modes
      • 1µA Shutdown Current
  • Logic-Level Translation on the Controller and Transceiver Interfaces Ensure System Compatibility
  • Register Compatible with MAX3107, MAX3108, and MAX148301

Product Details

The MAX3109 advanced dual universal asynchronous receiver-transmitter (UART) has 128 words of receive and transmit first-in/first-out (FIFO) and a high-speed SPI or I²C controller interface. The 2x and 4x rate modes allow a maximum of 24Mbps data rates. A phase-locked loop (PLL) and the fractional baud-rate generators allow a high degree of flexibility in baud-rate programming and reference clock selection.

Independent logic-level translation on the transceiver and controller interfaces allows ease of interfacing to microcontrollers, FPGAs, and transceivers that are powered by differing supply voltages. Automatic hardware and software flow control with selectable FIFO interrupt triggering offloads low-level activity from the host controller. Automatic half-duplex transceiver control with programmable setup and hold times allow the MAX3109 to be used in high-speed applications such as PROFIBUS-DP. The 128-word FIFOs have advanced FIFO control, reducing host processor data flow management.

The MAX3109 is available in a 32-pin TQFN (5mm x 5mm) package, and is specified over the -40°C to +85°C extended temperature range.


  • Automotive Infotainment Systems
  • Handheld Devices
  • HVAC or Building Control
  • Medical Systems
  • Point-of-Sales Systems
  • Power Meters
  • Programmable Logic Controllers (PLCs)

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Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

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ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

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