Multi-chip solution for USB-to-RS232 system development

July 12, 2013 // By Graham Prophet
USB solutions specialist FTDI Chip, through its X-Chip series, has now added to its portfolio of semiconductor solutions for USB-to-RS232 interfacing.

FTDI Chip’s USB-DUO offering bundles together one of the company’s high performance USB bridge controller ICs with its RS232 transceiver IC, in order to furnish engineers with a platform on which they can create their own USB-to-RS232 converter cabling systems - supporting speeds of up to 250 kbits/sec. The company’s FT231XS provides the USB-to-UART conversion operation while the FT3243S transceiver provides the digital-to-RS232 conversion, translating the 3.3 V level UART signal from the FT231XS to RS232 voltage levels.

The FT231XS’s internal EEPROM memory handles storage of USB configuration data and allows for customising of the device descriptors to match an OEM’s particular description preference. An internal phased-locked-loop (PLL) provides system timing. The FT3243S transceiver has a built-in transient voltage suppressor (TVS), complying with the EN6100-4-2 standard of ±15 kV for air gap discharge. This means that additional electro-static discharge (ESD) protection circuitry is not called for. By streamlining this offering, with a minimal number of external components being required, OEMs can reduce both the bill of materials (BoM) and the PCB area required to implement their complete system design.

The USB-DUO solution has very low overall power consumption, drawing 9 mA when it is active and 135 µA while its FT231XS X-Chip element is in suspend mode. With an operational temperature range covering -40 °C to 85 °C, this solution is suitable for use in demanding industrial settings.

“By combining two of our interface chips into one highly integrated product we can offer the industry a solution that is optimised for space constrained and cost-sensitive designs. This will allow engineers to bring the convenience of USB connectivity to legacy systems.” states Fred Dart, CEO and founder of FTDI Chip. The USB-DUO costs $1.98 (10,000).

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