SN75LBC777 SINGLE CHIP GEOPORT^TM/AppleTalk^TM TRANSCEIVER

SLLS227 - SEPTEMBER 1996

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features

• Single-Chip Interface Solution for the 9-Pin GeoPort^TM Peripheral Data Circuit- Terminating Equipment (DCE) for the Intelligent Network Port
• Designed to Operate up to 4-Mbits/s Full Duplex
• Single 5-V Supply Operation
• 10-kV ESD Protection on Bus Terminals
• Backward Compatible with AppleTalk^TM and LocalTalk^TM LANs
• Combines Multiple Components into a Single Chip Solution
• Complements the SN75LBC776 9-Terminal GeoPort Host Data Terminal Equipment (DTE) Interface Device
• LinBiCMOS^TM Process Technology

  GeoPort, LocalTalk, and AppleTalk are trademarks of Apple Computer, Incorporated. LinBiCMOS is a trademark of Texas Instruments Incorporated.

description

The SN75LBC777 is a low-power LinBiCMOS device that incorporate the drivers and receivers for a 9-pin GeoPort peripheral interface. GeoPort combines hybrid EIA/TIA-422-B and EIA/TIA-423-B drivers and receivers to transmit data up to four-Mbit/s full duplex. GeoPort is a serial communications standard that is intended to replace the RS-232, AppleTalk, and printer ports all in one connector in addition to providing real-time data transfer capability. The SN75LBC777 provides point-to-point connections between GeoPort-compatible devices with data transmission rates up to 4-Mbit/s full duplex over a 4-foot cable. Applications include connection to telephone, integrated services digital network (ISDN), digital sound and imaging, fax-data modems, and other traditional serial and parallel connections. The GeoPort is backwardly compatible to both LocalTalk and AppleTalk LANs.

While the SN75LBC777 is powered off (V_CC = 0) the outputs are in a high-impedance state. When the shutdown (SHDN) terminal is high, the charge pump is powered down and the outputs are in a high-impedance state. When high, the driver enable (DEN\) terminal puts the outputs of the differential driver into a high-impedance state.

A switched-capacitor voltage converter generates the negative voltage required from a single 5-V supply using two 0.33-uF capacitors. One capacitor is between the C+ and C- terminals and the other is between V_EE and ground.

The SN75LBC777 is characterized for operation over the 0°C to 70°C temperature range.

View more information about generic part numbers:SN75LBC777

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