The SN75LBC776 is the industryís first single-chip Geoport transceiver for nine-pin Universal Network Bus applications, enabling data transfer rates up to 4 million bits per second. This makes it ideal for applications such as high speed computer-to-digital telephone/PBX connections, digital still camera interfaces, and serial printer ports.
The Geoport interface is a serial data bus that transfers data over a cable from one piece of equipment to another. The typical system consists of a controller that implements the protocol, an 85C30 USART to serialize/deserialize the data and a SN75LBC776.
The transceiver is the link to the outside world and therefore the most vulnerable to hazards like ESD. The 'LBC776 helps to minimize these types of risks with high ESD protection, current- limiting and high-impedance outputs on shutdown and power-up.
The device operates from a single 5 V supply using small 0.1 µF charge pump capacitors. The maximum quiescent current is 15 mA; this is reduced to less than 100 µA during shutdown. Geoport allows high speed digital connections to telephony networks operating at ISDN and T1 data rates. Many more applications require isochronous data flows such as video conferencing and voice/data transfers. Analog modems or other PC add-in cards can include the high-speed digital Geoport link to increase interconnection options for a minimal additional expense.
The 'LBC776 replaces other discrete solutions with lower cost, reduced board space, fewer external components and higher ESD protection. The Geoport interface is the industry standard solution that is supported by multiple PC vendors and backward compatible to AppleTalk™, LocalTalk™, and RS-232. The 'LBC776 is available in a 20-pin wide-body SOIC package.
Literature numbers and device names: (Use the keyword search provided in the Semiconductor Technical Documentation page.)
SN75LBC776 D/S SLLS221A
Vol 15, February, 1996
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