A 10/100 Mb/s CMOS Ethernet transceiver for 10BaseT, 100BaseTX, and 100BaseFX

摘要

The IEEE 802.3 standard and the ANSI Fiber Distributed Data Interface (FDDI) standard define a 10 Mb/s twisted-pair standard, 10BaseTX, a 100 Mb/s twisted-pair standard, 100BaseTX, and a 100 Mb/s fiber standard, 100BaseFX. This chip incorporates the 10BaseTX, 100BaseTX, and 100BaseFx Transceivers. In the 100 Mb/s modes, 4 data bits are encoded into 5 bits that are sent at 125 Mb/s. In 100BaseFX mode, transmit data is NRZI encoded and is sent to an external fiber module as a differential quasi-ECL 125 Mb/s signal. Simultaneously, a differential quasi-ECL 125 Mb/s signal is received from the fiber module and decoded. In the twisted-pair mode, the chip negotiates with the far-end transceiver to either the 10BaseT or 100BaseTX mode. In the 10BaseT mode the chip uses Manchester coding. In the 100BaseTX mode, the chip uses MLT3 coding. The paper concentrates on the 100BaseTX mode.