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The MAX3100 universal asynchronous receiver transmitter (UART) is the first UART specifically optimized for small microcontroller-based systems. Using an SPI™/MICROWIRE™ interface for communication with the host microcontroller (µC), the MAX3100 comes in a compact 24-pin-TQFN and 16-pin QSOP. The asynchronous I/O is suitable for use in RS-232, RS-485, IR, and opto-isolated data links. IR-link communication is easy with the MAX3100's infrared data association (IrDA) timing mode.

The MAX3100 includes a crystal oscillator and a baud-rate generator with software-programmable divider ratios for all common baud rates from 300 baud to 230k baud. A software- or hardware-invoked shutdown lowers quiescent current to 10µA, while allowing the MAX3100 to detect receiver activity.

An 8-word-deep first-in/first-out (FIFO) buffer minimizes processor overhead. This device also includes a flexible interrupt with four maskable sources, including address recognition on 9-bit networks. Two hardware-handshaking control lines are included (one input and one output).

The MAX3100 is available in 14-pin plastic DIP and small, 16-pin QSOP packages in the commercial and extended temperature ranges.
MAX3100: Typical Operating Circuit MAX3100: Typical Operating Circuit Enlarge+

Key Features

  • Small TQFN and QSOP Packages Available
  • Full-Featured UART:
    • IrDA SIR Timing Compatible
    • 8-Word FIFO Minimizes Processor Overhead at High Data Rates
    • Up to 230k Baud with a 3.6864MHz Crystal
    • 9-Bit Address-Recognition Interrupt
    • Receive Activity Interrupt in Shutdown
  • SPI/MICROWIRE-Compatible µC Interface
  • Lowest Power:
    • 150µA Operating Current at 3.3V
    • 10µA in Shutdown with Receive Interrupt
  • +2.7V to +5.5V Supply Voltage in Operating Mode
  • Schmitt-Trigger Inputs for Opto-Couplers
  • TX and RTS Outputs Sink 25mA for Opto-Couplers


  • Handheld Instruments (PDAs, Palmtops)
  • Intelligent Instruments
  • Isolated RS-232/RS-485: Directly Drives Optocouplers
  • Low-Cost IR Data Links for Computers/Peripherals
  • Small Networks in HVAC or Building Control
  • UART in SPI Systems

See parametric specs for SPI/Microwire-Compatible UARTs (6)

Part NumberµP I/FChannelsICC
Package/PinsOper. Temp.
typSee Notes
MAX3100 SPI and Microwire Compatible10.272.7 to 5.5
-40 to +85
0 to +70
$4.06 @1k

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX3100EVKIT: Evaluation Kit for the MAX3100
Product Reliability Reports: MAX3100.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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