UARTs meet EIA/TIA-485 specifications.

Press Release Summary:

Operating from single 3-5.5 V supply at data rates up to 8 Mbps, series XR19L402/400 single/dual-channel 8-bit UARTs with integrated RS-485 transceiver work in active, partial sleep, full sleep, and power-save modes. They feature 64-bytes of transmit and receive FIFOs, automatic RTS/CTS hardware flow control, automatic Xon/Xoff and special character software flow control, transmit and receive FIFO trigger levels, and programmable fractional baud rate generator.

Original Press Release:

Exar Unveils Industry's First Single and Dual-Channel UART with Integrated RS-485 Transceiver Product Family -- Supports 8Mbps Data Rate

FREMONT, Calif., April 9 /- Exar Corporation (NASDAQ:EXAR), a leading provider of high-performance, mixed-signal silicon solutions for the worldwide communications infrastructure, today announced the industry's first single and dual-channel 8-bit Universal Asynchronous Receiver Transmitter (UART) with integrated RS-485 transceiver device family which supports data rates of up to 8Mbps. The XR19L402/400 series targets the growing market demand of industrial peripheral applications such as Point-of-Sale (POS), factory automation, and industrial networking systems amongst others.

"This launch is the result of ongoing technology development, and marks another step in Exar's continuing effort to extend the reach of its serial communications expertise to integrate adjacent device functionality onto our UART products." said Levent Ozcolak, vice president of marketing, Interface Products. "By incorporating RS-485 transceiver capabilities, Exar is delivering more design options to customers while preserving common product architecture for both current and next generation applications."

Product Series Details

The XR19L402/400 series offers different packaging and modem interface options. Both devices can operate in four different modes: active, partial sleep, full sleep and Power-Save. Each mode can be invoked via hardware or software. Upon power-up, the device is in the active mode where the UART and RS-485 transceiver function normally. In the partial sleep mode, the internal crystal oscillator of the UART, or the charge pump of the RS-485 transceiver, is turned off. In full sleep mode, both the crystal oscillator and the charge pump are turned off. While the UART is in the sleep mode, the Power-Save mode isolates the core logic from the control signals (chip select, read/write strobes, address and data bus lines) to minimize the power consumption. The RS-485 receivers remain active in each of these four modes.

The devices operate from a single +3V to 5.5V supply with data rates up to 8Mbps, while meeting all EIA/TIA-485 specifications. The configuration register set is 16550 UART compatible for control, status and data transfer. Also, the devices have 64-bytes of transmit and receive FIFOs, automatic RTS/CTS hardware flow control, automatic Xon/Xoff and special character software flow control, transmit and receive FIFO trigger levels, and a programmable fractional baud rate generator with a prescaler of divide by 1 or 4. Additionally, the devices include an ACP pin which allows the user to shut down the charge pump for the RS-485 drivers. In the UART portion, the Power-Save feature isolates the data bus interface to further reduce power consumption in the sleep mode.

"Because both devices support 64 bytes of transmit and receive FIFO, increased performance is realized as the system allows the external processor to handle more networking tasks within a given time," said Eric Nguyen, senior strategic marketing manager, Interface Products. "In addition, the devices provide ACP and Power-Save modes that drastically reduce power consumption when the device is not used. The combination of features greatly reduces the CPU's bandwidth requirement, increases performance, and reduces power consumption."

Fourteen Industry Firsts

The XR19L402 and XR19L400 mark Exar's thirteenth and fourteenth industry-first products in two years. In February 2007, Exar announced the XR20M1172 and XR20V2172; in January 2007, the Company launched the XR19L2x2 8-bit dual-channel UART and RS-232 combination series; in December 2006, the Company launched the XR20M1170 (1.8V) and XR20V2170 I2C/SPI UART with an integrated RS-232 transceiver; in August 2006, Exar introduced the XR17V254 a quad-channel 66MHz PCI 3.0 compliant UART. In June 2006, Exar released the XR16V2x5x series of 16Mbps dual UARTs; in April 2006, Exar launched the single-channel UART and RS-232 combination, the XR19L2xx series; in February 2006, Exar released the XR17V252 a dual-channel 66MHz PCI 3.0 compliant UART; in December 2005, Exar introduced the industry's first 1.8V single-channel UART (XR16L570) in 24 and 32-pin QFN packages; in June 2005, Exar added the industry's smallest UART (XR16L580); lastly, in March 2005, Exar introduced a multi-channel 66MHz PCI 3.0 compliant UART family, the first in this series was an eight-channel (XR17V258) solution.

Tools and Support

The XR19L402/400 series supports standard serial port drivers as well as Windows CE drivers. With the availability of software drivers and Exar's application support line, customers can accelerate their time to market by minimizing driver development, testing and diagnostic procedures.

Packages, Prices, Availability and Additional Information

The XR19L402 is offered in a 48-pin QFN, and is priced at the mid-$4 range in 1,000 piece quantities. Additional information on this product can be found at The XR19L400 is offered in a 40-pin QFN, and is priced at mid-$2 range in 1,000 piece quantities. Additional information on this product can be found at Both devices are available for sampling now. Additional information on other UART products can be found at

About Exar

Exar Corporation designs, develops and markets high-performance, analog and mixed-signal silicon solutions for a variety of markets including networking, serial communications, and storage. Leveraging its industry-proven analog design expertise and system-level knowledge, Exar delivers to customers a wide array of technology solutions for current as well as next generation products. The Company is based in Fremont, CA, had fiscal 2006 revenues of $67.0 million, and employs approximately 235 people worldwide. For more information about the Company visit:

Source: Exar Corporation

Greg Kaufman,
Marketing Communications, of Exar Corporation,

Web site:

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