January 1997
ML6680
Token Ring Copper-to-Fiber Converter
GENERAL DESCRIPTION
The ML6680 is a single-chip conversion between Token
Ring ISO/IEC8802-5 copper-based media and Token Ring
ISO/IEC8802-5 fiber-based media. The ML6680 fiber-optic
interface contains a data quantizer, circuitry for fiber optic
key signal generation and recognition, pin-selectable
signal switching, and current driven transmitter outputs.
The ML6680 copper interface consists of a twisted pair
line equalizer, receive squelch circuit, pin selectable
phantom wire fault detection and signal switching, and a
transmit driver. This section supports the ISO/IEC8802-5
standard requirements. The ML6680 provides an optional
PECL compatible interface.
The ML6680 may be configured to one of four modes:
1.
2.
3.
4.
Standard Media Converter
Concentrator Media Converter
Lobe or Ring Out Port Media Converter
Ring In Port Media Converter
FEATURES
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Single-chip copper-to-fiber converter for Token Ring
16Mbps and 4Mbps data rates with the same
external components
Four modes of operation covering a wide variety
of applications
Full duplex operation
Highly stable data quantizer with 55dB input
dynamic range
Current driven fiber optic LED driver for accurate
launch power
Current driven output for low RFI noise and low jitter
Capable of driving 100Ω UTP or 150Ω STP
Pin selectable phantom wire fault detection and
signal switching
BLOCK DIAGRAM
EQA
TPINP
TPINN
TWISTED PAIR
EQUALIZER
LED
DRIVER
EQB
RTSETOP
OPVCC
OPOUT
TPINOK
TWISTED PAIR
RECEIVE SQUELCH
SIGNAL
MUX
FIBER OPTIC
RECEIVE SQUELCH
OPINOK
RTSETTP
TPOUTP
TPOUTN
TWISTED PAIR
DRIVER
FIBER OPTIC
QUANTIZER
OPINP
OPINN
VDC
PHTM1
PHTM2
PHANTOM
DRIVER
CONTROL
LOGIC
BIAS
XTAL1
CRYSTAL
OSCILLATOR
XTAL2
KEYGEN
INSERTED
1
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
