MAX3109ETJ+T

The MAX3109ETJ+T from Analog Devices is an advanced dual SPI/I2C UART, designed to bridge microcontroller buses to asynchronous serial interfaces such as RS-485, RS-232, and IrDA. Each UART channel features 128-word TX and RX FIFOs that significantly offload the host processor. The integrated PLL and fractional baud-rate generator provide high-resolution programmable baud rates up to 24 Mbps. Independent logic-level translation on both controller and transceiver interfaces ensures compatibility between different voltage domains. With automatic hardware and software flow control, 9-bit multidrop mode, and special character detection, this device simplifies serial communication system design.

The MAX3109ETJ+T operates as a bridge between a host controller (via SPI or I2C) and two independent asynchronous serial channels. The host writes TX data to the TX FIFO through the SPI/I2C interface, and the UART serializer transmits the data bit-by-bit on the TX pin. Received data on the RX pin is deserialized, checked for errors, and placed in the RX FIFO for the host to read. The fractional baud-rate generator and integrated PLL allow precise baud-rate synthesis from a wide range of reference clocks. The 128-word FIFOs buffer data between the host and serial ports, reducing interrupt frequency. Automatic flow control (RTS/CTS hardware and XON/XOFF software) manages data flow without host intervention. The IrDA encoder/decoder handles SIR and MIR infrared protocols.

• Industrial PLCs and PROFIBUS-DP communication systems
• Automotive infotainment requiring multiple serial channels
• Smart grid power meters with RS-485 metering interfaces
• Medical systems needing isolated serial communication
• Point-of-sale terminals with multi-port serial connectivity