LXT6155LE datasheet(13/50 Pages) INTEL

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Datasheet

155 Mbps SDH/SONET/ATM Transceiver — LXT6155

2.0

Functional Description

The LXT6155 is a front-end transceiver designed for 155 Mbps OC3/STM1/ATM transmission

applications. Table 2 lists the standards with which the LXT6155 is compliant.

The LXT6155 interfaces to either a fiber transceiver or a coax cable on the line side, and on the

system side, to an SDH/SONET Overhead Terminator or an ATM UNI. The LXT6155 can function

in Hardware stand-alone mode, or in Software mode controlled through an industry standard

Motorola compatible 4-wire serial microprocessor interface.

The LXT6155 can be set to operate in either CMI mode for the 75

Ω coax interface or NRZ mode

for the optical transceiver interface. The operating mode can be set in either hardware mode by

using the MODE pin, or software mode by using Primary Control Register, bit 0.

2.1

Transmitter

In serial mode, the LXT6155 accepts both data (TPOS, TNEG) and clock signals (TSICLKP,

TSICLKN). Serial clock signals are required for the LXT6155 to run internal logic, reshape the

line transmit pulses and generate the low-jitter clocks for Tx data generation.

In parallel mode, the LXT6155 accepts data TPID<7:0> and clock TPICLK. TPICLK is internally

multiplied by 8 to yield the 155.52 MHz clock for Tx data generation.

Both serial and parallel clocks (TSICLKP/TSICLKN and TPICLK) must conform to the SONET/

SDH standard frequency accuracy requirements.

Depending on whether the selected media interface is coax or fiber, the data is CMI or NRZ

encoded respectively, and passed to the appropriate line drivers. The LXT6155 line drivers are

high-speed buffers that meet the CMI templates and industry standard LVPECL signal

requirements. The CMI output pins are TTIP0 and TRING0, and the NRZ LVPECL pins, TTIP1

and TRING1.

2.1.1

Transmitted Signal

Transmitted signals conform to the standard templates listed in Table 2.

2.1.1.1

Fiber Based G.957/GR-253 Transmission Systems

The LXT6155 provides 3.3V LVPECL compatible signals for interfacing to a fiber optic

transceiver. Please refer to Application Information for interface schematics.

2.1.2

Coax Based G.703/GR-253 Transmission Systems

The LXT6155 encodes and decodes CMI signals that are transmitted onto a 75

Ω coax cable

compliant with STM1/STS-3 CMI templates. Please refer to the CMI templates shown in Figures

24 and 25.

LXT6155LE Datasheet(PDF) 13 Page - Intel Corporation