Datasheet

3

T1/E1 Short Haul Transceiver with Crystal-less Jitter Attenuation — LXT351

Contents

1.0

Pin Assignments and Signal Descriptions......................................................8

1.1

Mode Dependent Signals ...................................................................................... 9

2.0

Functional Description...........................................................................................13

2.1

Initialization.......................................................................................................... 13

2.1.1

Reset Operation ..................................................................................... 13

2.2

Transmitter .......................................................................................................... 13

2.2.1

Transmit Digital Data Interface ...............................................................13

2.2.2

Transmit Monitoring................................................................................ 14

2.2.3

Transmit Drivers ..................................................................................... 14

2.2.4

Transmit Idle Mode................................................................................. 14

2.2.5

Transmit Pulse Shape ............................................................................14

2.3

Receiver .............................................................................................................. 15

2.3.1

Receive Data Recovery.......................................................................... 15

2.4

Jitter Attenuation ................................................................................................. 15

2.5

Diagnostic Mode Operation................................................................................. 16

2.5.1

Loopback Modes .................................................................................... 16

2.5.1.1 Local Loopback ......................................................................... 16

2.5.1.2 Analog Loopback....................................................................... 18

2.5.1.3 Remote Loopback .....................................................................18

2.5.1.4 Dual Loopback .......................................................................... 19

2.5.2

Internal Pattern Generation .................................................................... 19

2.5.2.1 Transmit All Ones ...................................................................... 19

2.5.2.2 Quasi-Random Signal Source (QRSS) .....................................20

2.5.3

Error Insertion and Detection ................................................................. 21

2.5.3.1 Bipolar Violation Insertion (INSBPV) ......................................... 21

2.5.3.2 Logic Error Insertion (INSLER)..................................................21

2.5.3.3 Bipolar Violation Detection (BPV).............................................. 21

2.5.3.4 HDB3 Code Violation Detection (CODEV) ................................ 21

2.5.3.5 HDB3 Zero Substitution Violation Detection (ZEROV) .............. 21

2.5.4

Alarm Condition Monitoring .................................................................... 22

2.5.4.1 Loss of Signal ............................................................................22

2.5.4.2 Alarm Indication Signal Detection ............................................. 22

2.5.4.3 Driver Failure Open Mode ......................................................... 22

2.5.4.4 Elastic Store Overflow/Underflow .............................................. 22

2.5.4.5 Built-In Self Test ........................................................................ 23

2.6

Parallel Microprocessor Interface........................................................................ 23

2.6.1

Interrupt Handling................................................................................... 23

3.0

Register Definitions.................................................................................................24

4.0

Application Information.........................................................................................29

4.1

Transmit Return Loss .......................................................................................... 29

4.2

Transformer Data ................................................................................................ 29

4.3

Application Circuit................................................................................................ 29

4.4

Line Protection .................................................................................................... 29

4.4.1

LXT351 Application Circuit .....................................................................31