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 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.

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

Applications/Uses

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