INTEGRATED UART AND RS-485 IN 28-PIN QSOP SAVES SPACE AND SIMPLIFIES NETWORK INSTALLATION
SUNNYVALE, CA—May 11, 1999—Maxim Integrated Products introduces the MAX3140, a complete universal asynchronous receiver-transmitter (UART) and RS-485 transceiver in a single 28-pin package. The MAX3140 saves additional board space and microcontroller I/O pins by featuring an SPI/MICROWIRE-compatible serial interface. It simplifies installation of RS-485/RS-422 networks by providing pin-programmable network configuration.
The MAX3140 includes a single RS-485/RS-422 driver and receiver featuring true fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This feature provides immunity to faults without requiring complex termination. The MAX3140 provides software-selectable control of half/full-duplex, data/slew rate, and phase control. The transceiver data rate is programmable to 115kbps, 500kbps, and 10Mbps to control slew rate and minimize EMI. Independent transmitter/receiver phase control enables software correction of twisted-pair polarity reversal.
The UART includes a crystal oscillator and baud-rate generator with software-programmable divider ratios for common baud rates. It features an eight-word-deep receive FIFO that minimizes processor overhead and provides a flexible interrupt with four maskable sources, including address recognition on 9-bit networks.
The MAX3140 operates from a single +5V supply and has a hardware- or software-invoked 20µA shutdown mode with receive interrupt active. It is available in a space-saving 28-pin QSOP package with prices starting from $4.07 (1000-up, FOB USA). | 
