LXT6155 — 155 Mbps SDH/SONET/ATM Transceiver

10

Datasheet

16

17

18

19

TPID7/TXTRIM3

TPID6/TXTRIM2

TPID5/TXTRIM1

TPID4/TXTRIM0

DI

TTL

Transmit Parallel Input Data. Transmit data from an Overhead

Terminator at parallel speed 19.44 MHz, clocked in by TPICLK. TPID7 is

the most significant bit, and is the first bit to be sent. These pins should

be grounded or not connected when the LXT6155 is used in serial mode.

Transmit Trim Controls, in serial, hardware, coax mode only. These

pins trim the amplitude of the line driver output from (nom -21%) to (nom

+24%) in 3% steps. This feature is only enabled when pin #20

(TXTRIMENA) is High.

20

TPID3/TXTRIMENA

DI

TTL

Transmit Parallel Input Data. Transmit data from an Overhead

Terminator at parallel speed 19.44 MHz, clocked in by TPICLK. TPID7 is

the most significant bit, and is the first bit to be sent. These pins should

be grounded or not connected when the LXT6155 is used in serial mode.

Transmit Trim Enable, in serial, hardware, coax mode only. This pin

enables the trimming of the line driver output by pins 16-19 when high.

21

22

23

TPID2

TPID1

TPID0

DI

TTL

Transmit Parallel Input Data. Transmit data from an Overhead

Terminator at parallel speed 19.44 MHz, clocked in by TPICLK. TPID7 is

the most significant bit, and is the first bit to be sent. These pins should

be grounded or not connected when the LXT6155 is used in serial mode.

24

TPICLK

DI

TTL

Transmit Parallel Input Clock. Parallel transmit clock at 19.44 MHz.

This pin is disabled when serial mode is selected and should be

grounded or not connected.

25

VCC

S

Power Supply.

26

RPOCLK

DO

TTL

Receive Parallel Output Clock. Parallel receive clock as recovered

from received data. The clock is nominally 19.44 MHz, synchronized with

RPOD<7:0>.

27

28

29

30

31

32

33

34

RPOD7

RPOD6

RPOD5

RPOD4

RPOD3

RPOD2

RPOD1

RPOD0

DO

TTL

Receive Parallel Output Data. RPOD<7:0> output aligned 8-bit bytes at

RPOCLK clock rate. These pins are to be left open when serial mode is

selected. RPOD7 is the most significant bit, and is the first to arrive.

35

GND

S

Ground.

36

RSOCLKP

DO

LVPECL

Receive Serial Output Clock. Serial receive clock as recovered from

received data. The clock is nominally 155.52 MHz, synchronized with

output serial data RPOS and RNEG.

37

RSOCLKN

38

PVCC

S

PECL Buffers Power Supply.

39

RNEG

DO

LVPECL

Receive Serial Output Data, positive and negative.These two pins

provide recovered data synchronized to receive serial output clocks

RSOCLKP and RSOCLKN. These pins are tristated and should be left

open when parallel mode is selected.

40

RPOS

41

RDVCC

S

Receive Digital Power Supply.

42

RDGND

S

Receive Digital Ground.

Table 1.

LXT6155 Pin Descriptions (Continued)

Pin #

Symbol

Description

1. DI = Digital Input; DO = Digital Output; DI/O = Digital Input/Output; AI = Analog Input; AO = Analog Output; AI/O = Analog Input/Output; S=Supply.

2. TTL = Transistor-to-Transistor Logic (5V tolerant); LVPECL = Low-Voltage positive ECL.