Inside
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High-Speed Peripheral GeoPort™/AppleTalk™ TransceiversProduct Features
The SN75LBC777 is a low-power LinBiCMOS device that incorporates
the drivers and receivers for a 9-pin GeoPort peripheral interface
and a switched-capacitor voltage converter for single 5-V supply
operation. GeoPort combines hybrid EIA/TIA-422-B and EIA/TIA-423-B
drivers and receivers to transmit data up to 4 Mbps, full duplex.
The SN75LBC777 is designed to meet the GeoPort and AppleTalk standards.
The peripheral manufacturer may easily integrate high-speed Power
PC serial bus connections with a single transceiver that compliments
the successful GeoPort/AppleTalk host transceivers, the SN75LBC771
and SN75LBC776. With high ESD protection, these devices minimize
costly field failures and allow hot plug-and-play features.
All three devices reduce power consumption to less than 500 µW in shutdown mode. While the SN75LBC777 is powered-off (VCC = 0) the outputs are in a high impedance state. When the shutdown (SHDN) pin is high, the charge pump will be powered down and the outputs are in a high-impedance state. With a high input signal, the driver enable (DEN) terminal puts the outputs of the differential driver into a high-impedance state. The charge pumps on the SN75LBC776 and SN75LBC777 allow single +5V supply operation. They only require 75 mW (max) of no-load power. The SN75LBC771 uses ±5V power supplies to reduce component and systems level costs for systems with both supplies available. Applications include connection to telephony, ISDN, digital sound and imaging, fax-data modems and other serial and parallel connections. The GeoPort is backwardly compatible to both LocalTalkª and AppleTalk. These devices are available in 20-pin SOIC packaging.
Vol 19, October, 1996 |
