XRT5997 [EXAR]
Seven-Channel E1 Line Interface Unit; 七路E1线路接口单元
| 型号： | XRT5997 |
| 厂家： | 
EXAR CORPORATION |
| 描述： | Seven-Channel E1 Line Interface Unit |
| 文件： | 总37页 (文件大小：253K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
XRT5997
Seven-Channel E1
Line Interface Unit
November 1999-2
FEATURES
The Main features are as follows:
l Logic Inputs Accept Either 3.3V or 5.0V Levels
l OperatesovertheIndustrialTemperatureRange
l Ultra Low Power Dissipation
l ConsistsofSeven(7)IndependentE1(CEPT)
Line Interface Units (Transmitter and Receiver)
l Generates Transmit Output Pulses that are
Compliant with the ITU-T G.703 Pulse Template
Requirementfor2.048Mbps(E1)Rates
l +3.3VSupplyOperation
APPLICATIONS
l On-Chip Pulse Shaping for both 75Ω and 120Ω
linedrivers
l PDHMultiplexers
l ReceiverCanEitherBeTransformeror
l SDHMultiplexers
l Digital Cross-Connect Systems
l DECT(DigitalEuropeanCordlessTelephone)
Base Stations
Capacitive-CoupledtotheLine
l Detects and Clears LOS (Loss of Signal) Per
ITU-TG.775
l CSU/DSUEquipment
l Compliant with the ITU-T G.823 Jitter Tolerance
Requirements
l Compliant with ITU G. 703 EOS Over-voltage
protectionRequirement
GENERALDESCRIPTION
EachReceiverinputcanbetransformerorcapacitive-
coupledtotheline. TheReceiverinputistransformer-
coupledtotheline,usinga2:1step-downtransformer.
EachTransmitteriscoupledtothelineusinga1:2step-
up transformer. This same configuration is applicable
for both balanced (120Ω ) and unbalanced (75Ω )
interfaces.
The XRT5997 is an optimized seven-channel analog
E1 line interface unit fabricated using low power 3.3V
CMOS technology. Each channel consists of both a
Transmitter and a Receiver function. The Transmitter
acceptsaTTLorCMOSlevelsignalfromtheTerminal
Equipment;andoutputsthisdatatothelineviabipolar
pulses that are compliant to the ITU-T G.703 pulse
template for E1. The Receiver accepts an attenuated
bipolarlinesignal(fromtheremoteterminalequipment)
andoutputsthisdatatothe(near-end)terminalequip-
ment via CMOS level signals.
ORDERINGINFORMATION
Part No.
Package
Operating
Temperature Range
-40°C to +85°C
XRT5997IV
100-Lead TQFP (14 x 14 x 1.4 mm)
Rev. 1.0.0
EXARCorporation, 48720KatoRoad, Fremont, CA94538 • (510)668-7000 • FAX(510)668-7017• www.exar.com
XRT5997
Channel 7
Channel 6
Channel 5
Channel 4
Channel 3
RxLOS
Channel 2
RTIP
RxPOS
RxNEG
Peak Detector/
Receive
LOS
Receive Output
Equalizer
Slicer
Detector
Interface
RRing
TTIP
TxPOS
TxNEG
TxClk
Pulse Shaping
Transmit Input
Circuit
Interface
TRing
Figure 1. XRT5997 Block Diagram
Rev. 1.0.0
2
XRT5997
PINCONFIGURATION
RxPOS6
75
74
73
RxPOS1
RxNEG1
DVDD
1
2
RxNEG6
DGND
3
4
5
6
7
8
AGND
72
71
LOS7
RT IP6
RxPOS7
70
69
RRing6
RT IP7
RxNEG7
RT IP1
RRing1
AVDD
RRing7
AVDD
68
67
66
65
9
AGND
AVDD
AGND
AVDD
10
100-Pin
TQFP
XRT5997IV
11
12
RRing5
RT IP5
TGND5
64
63
62
61
RRing2
RT IP2
AGND
13
14
15
16
TT IP5
TT IP2
TVDD5
60
59
TVDD2
TRing5
TGND4
TRing2
TGND2
TRing3
TVDD3
17
18
19
20
58
57
56
55
54
53
52
51
TRing4
TVDD4
TT IP4
TT IP3
21
22
DGND
RT IP4
TGND3
RT IP3
23
24
25
RRing4
TxClk4
RRing3
TxClk3
100 LEAD THIN QUAD FLAT PACK
(14 x 14 x 1.4 mm., TQFP)
Rev. 1.0.0
3
XRT5997
PINDESCRIPTION
Pin#
Symbol
Type
Description
1
RxPOS1
O
Receiver 1 Positive Data Out:
This output pin will pulse “high” whenever Channel 1, within the XRT5997
device has received a “Positive Polarity” pulse, in the incoming line signal,
at RTIP1/RRing1 inputs.
2
RxNEG1
O
Receiver 1 Negative Data Out:
This output pin will pulse “high” whenever Channel 1, within the XRT5997
device has received a “Negative Polarity” pulse, in the incoming line signal,
at tRTIP1/RRing1 inputs.
3
4
DVDD
LOS7
-
Positive Supply - (+3.3V ± 5%). Digital Circuitry.
O
Receiver 7 Loss of Signal Output Indicator:
This output pin toggles “high” if Channel 7, within the XRT5997 device has
detected a “Loss of Signal” condition in the incoming line signal.
5
6
RxPOS7
RxNEG7
O
O
Receiver 7 Positive Data Out:
This output pin will pulse “high” whenever Channel 7, within the XRT5997
device has received a “Positive Polarity” pulse, in the incoming line signal,
at RTIP7/RRing7 inputs.
Receiver 7 Negative Data Out:
This output pin will pulse “high” whenever Channel 7, within the XRT5997
device has received a “Negative Polarity” pulse, in the incoming line signal,
at RTIP7/RRing7 inputs.
7
8
RTIP1
I
I
Receiver 1 Positive Bipolar Input:
The Receive Section of Channel 1 uses this input pin, along with RRing1
to receive the bipolar line signal from the “Remote E1 Terminal”.
RRing1
Receiver 1 Negative Bipolar Input:
The Receive Section of Channel 1 uses this input pin, along with RTIP1 to
receive the bipolar line signal from the “Remote E1 Terminal”.
9
AVDD
AGND
AVDD
RRing2
-
-
Positive Supply - (+3.3V ± 5%). Analog Circuitry.
AnalogGround
10
11
12
Positive Supply - (+3.3V ± 5%). Receiver 1, 2, 3, 5.
I
I
Receiver 2 Negative Bipolar Input:
The Receive Section of Channel 2 uses this input pin, along with RTIP2 to
receive the bipolar line signal from the “Remote E1 Terminal”.
13
RTIP2
Receiver 2 Positive Bipolar Input:
The Receive Section of Channel 2 uses this input pin, along with RRing2
to receive the bipolar line signal from the “Remote E1 Terminal”.
Rev. 1.0.0
4
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
14
15
AGND
TTIP2
-
Analog Ground - Receiver 1, 2, 3, 5.
O
Transmitter 2 Positive Bipolar Output:
Channel 2 within the XRT5997 device will use this pin, along with TRing2,
to transmit a bipolar line signal, via a 1:2 step-up transformer.
16
17
TVDD2
TRing2
-
Positive Supply - (+3.3V ± 5%), Transmitters 2.
O
Transmitter 2 Negative Bipolar Output:
Channel 2 within the XRT5997 device will use this pin, along with TTIP2, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
18
19
TGND2
TRing3
Digital Ground - Transmitters 2.
O
O
Transmitter 3 Negative Bipolar Output:
Channel 3 within the XRT5997 device will use this pin, along with TTIP3, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
20
21
TVDD3
TTIP3
Positive Supply - (+3.3V ± 5%), Transmitters 3.
Transmitter 3 Positive Bipolar Output:
Channel 3 within the XRT5997 device will use this pin, along with TRing3,
to transmit a bipolar line signal, via a 1:2 step-up transformer.
22
23
TGND3
RTIP3
Digital Ground - Transmitters 3.
I
I
I
Receiver 3 Positive Bipolar Input.
The Receive Section of Channel 4 uses this input pin, along with RRing3
to receive the bipolar line signal from the “Remote E1 Terminal”.
24
25
RRing3
TxClk3
Receiver 3 Negative Bipolar Input.
The Receive Section of Channel 3 uses this input pin, along with RTIP3 to
receive the bipolar line signal from the “Remote E1 Terminal”.
Transmitter Clock Input – Channel 3:
If the user operates Channel 3 (within the XRT5997 device) in the “clocked”
mode, then the “Transmit Section” of the Channel 3 will use the falling edge
of this signal to sample the data at the TxPOS3 and TxNEG3 input pins.
Note: If the user operates the Channel 3 in the “clockless” mode, then the
Terminal Equipment should not apply a clock signal to this input pin.
Rev. 1.0.0
5
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
26
TxNEG3
I
Transmitter - Negative Data Input – Channel 3:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 3) in
the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input
pin, whenever the Terminal Equipment needs to transmit a “negative-
polarity” pulse onto the line via TTIP3 and TRing3 output pins. The
XRT5997 device will sample this input pin upon the falling edge of the
TClk3 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime
the Terminal Equipment needs to transmit a “negative-polarity” pulse onto
the line viaTTIP3 and TRing3 output pins.
27
TxPOS3
I
Transmitter - Positive Data Input – Channel 3:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 3) in
the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input
pin, whenever the Terminal Equipment needs to transmit a “positive-
polarity” pulse onto the line via TTIP1 and TRing1 output pins. The
XRT5997 device will sample this input pin upon the falling edge of the
TClk1 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime
the Terminal Equipment needs to transmit a “positive-polarity” pulse onto the
line via TTIP1 and TRing1 output pins).
28
29
LOS3
O
O
Receiver 3 – Loss of Signal Output Indicator:
This output pin toggles “high” if Channel 3, within the XRT5997 device has
detected a “Loss of Signal” condition in the incoming line signal.
RxPOS3
Receiver 3 Positive Data Out:
This output pin will pulse “high” whenever Channel 3, within the XRT5997
device has received a “Positive Polarity” pulse, in the incoming line signal, at
RTIP3/RRing3 inputs.
Rev. 1.0.0
6
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
30
RxNEG3
O
Receiver 3 Negative Data Out:
This output pin will pulse “high” whenever Channel 3, within the XRT5997
device has received a “Negative Polarity” pulse, in the incoming line signal,
at RTIP3/RRing3 inputs.
31
32
33
TxPOS2
TxNEG2
TxClk2
I
I
I
Transmitter - Positive Data Input – Channel 2:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 2) in
the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “positive-polarity”
pulse onto the line via TTIP2 and TRing2 output pins). The XRT5997
device will sample this input pin upon the falling edge of the TClk2 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime
the Terminal Equipment needs to transmit a “positive-polarity” pulse onto the
line via TTIP2 and TRing2 output pins.
Transmitter - Negative Data Input – Channel 2:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of the Channel 2)
in the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “negative-polarity”
pulse onto the line via TTIP2 and TRing2 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk2 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “negative-polarity” pulse onto the
line via TTIP2 and TRing2 output pins.
Transmitter Clock Input – Channel 2:
If the user operates Channel 2 (within the XRT5997 device) in the “clocked”
mode, then the “Transmit Section” of the Channel 2 will use the falling edge
of this signal to sample the data at the TxPOS2 and TxNEG2 input pins.
Note If the user operates the Channel 2 in the “clockless” mode, then the
Terminal Equipment should not apply a clock signal to this input pin.
1
Note: Internally pull-up with 50K resistor.
Rev. 1.0.0
7
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
34
RxNEG2
O
Receiver 2 Negative Data Out:
This output pin will pulse “high” whenever Channel 2, within the XRT5997
device has received a “Negative Polarity” pulse, in the incoming line signal,
at RTIP2/RRing2 inputs.
35
36
RxPOS2
LOS2
O
O
Receiver 2 Positive Data Out:
This output pin will pulse “high” whenever Channel 2, within the XRT5997
device has received a “Positive Polarity” pulse, in the incoming line signal, at
RTIP2/RRing2 inputs.
Receiver 2 Loss of Signal:
This output pin toggles “high” if Channel 2, within the XRT5997 device has
detected a “Loss of Signal” condition in the incoming line signal.
37
38
39
40
DVDD
DVDD
DGND
LOS5
-
-
Positive Supply (+3.3V ± 5%). Digital Circuitry.
Positive Supply (+3.3V ± 5%). Digital Circuitry.
Digital Ground: Digital Circuitry.
-
O
Receiver 5 Loss of Signal:
This output pin toggles “high” if Channel 5, within the XRT5997 device has
detected a “Loss of Signal” condition in the incoming line signal.
Note: 1Internally pull-up with 50K resistor
41
42
43
RxPOS5
RxNEG5
TxClk5
O
O
I
Receiver 5 Positive Data Out:
This output pin will pulse “high” whenever Channel 5, within the XRT5997
device has received a “Positive Polarity” pulse, in the incoming line signal, at
RTIP5/RRing5 inputs.
Receiver 5 Negative Data Out:
This output pin will pulse “high” whenever Channel 5, within the XRT5997
device has received a “Negative Polarity” pulse, in the incoming line signal,
at RTIP5/RRing5 inputs.
Transmitter Clock Input – Channel 5:
If the user operates Channel 5 (within the XRT5997 device) in the “clocked”
mode, then the “Transmit Section” of the Channel 5 will use the falling edge of
this signal to sample the data at the TxPOS5 and TxNEG5 input pins.
NOTE: If the user operates the Channel 5 in the “clockless” mode, then the
Terminal Equipment should not apply a clock signal to this input pin.
1
Note: Internally pull-up with 50K resistor.
Rev. 1.0.0
8
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
44
TxNEG5
I
Transmitter - Negative Data Input – Channel 5:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of the Channel 5)
in “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “negative-polarity”
pulse onto the line via TTIP5 and TRing5 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TCLK5 signal.
Clockless Mode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime
the Terminal Equipment needs to transmit a “negative-polarity” pulse onto the
line via TTIP5 and TRing5 output pins.
45
TxPOS5
I
Transmitter - Positive Data Input – Channel 5:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 5) in
the “Clocked” or “Clockless” Mode.
Clocked Mode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “positive-polarity”
pulse onto the line via TTIP5 and TRing5 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk5 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “positive-polarity” pulse onto the line
via TTIP5 and TRing5 output pins.
46
47
RxNEG4
RxPOS4
O
O
Receiver 4 Negative Data Out:
This output pin will pulse “high” whenever Channel 4, within the XRT5997
device has received a “Negative Polarity” pulse, in the incoming line signal,
at the RTIP4/RRing4 inputs.
Receiver 4 Positive Data Out:
This output pin will pulse “high” whenever Channel 4, within the XRT5997
device has received a “Positive Polarity” pulse, in the incoming line signal, at
RTIP4/RRing4 inputs.
Rev. 1.0.0
9
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
48
LOS4
O
Receiver 4 Loss of Signal:
This output pin toggles “high” if Channel 4, within the XRT5997 device has
detected a “Loss of Signal” condition in the incoming line signal.
49
TxPOS4
TxNEG4
TxClk4
O
Transmitter - Positive Data Input – Channel 4:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 4) in
the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “positive-polarity”
pulse onto the line via TTIP4 and TRing4 output pins). The XRT5997
device will sample this input pin upon the falling edge of the TClk4 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime
the Terminal Equipment needs to transmit a “positive-polarity” pulse onto the
line via TTIP4 and TRing4 output pins.
50
I
Transmitter - Negative Data Input – Channel 4:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of the Channel 4)
in the “Clocked” or “Clockless” Mode.
In the Clocked Mode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “negative-polarity”
pulse onto the line via the TTIP4 and TRing4 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk4 signal.
In the Clockless Mode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “negative-polarity” pulse onto the
line (via the TTIP4 and TRing4 output pins).
51
I
Transmitter Clock Input – Channel 4:
If the user operates Channel 4 (within the XRT5997 device) in the “clocked”
mode, then the “Transmit Section” of the Channel 4 will use the falling edge of
this signal to sample the data at the TxPOS4 and TxNEG4 input pins.
Note: If the user operates the Channel 4 in the “clockless” mode, then the
Terminal Equipment should not apply a clock signal to this input pin.
52
RRing4
I
Receiver 4 Negative Bipolar Input:
The Receive Section of Channel 4 uses this input pin, along with RTIP4 to
receive the bipolar line signal from the “Remote E1 Terminal”.
Rev. 1.0.0
10
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
53
RTIP4
I
Receiver 4 Positive Bipolar Input.
The Receive Section of Channel 4 uses this input pin, along with RRing4 to
receive the bipolar line signal from the “Remote E1 Terminal”.
54
55
DGND
TTIP4
Digital Ground. Digital Circuitry.
O
O
O
O
Transmitter 4 Positive Bipolar Output.
Channel 4 within the XRT5997 device will use this pin, along with TRing4, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
56
57
TVDD4
TRing4
Positive Supply (+3.3V ± 5%), Transmitters 4.
Transmitter 4 Negative Bipolar Output.
Channel 4 within the XRT5997 device will use this pin, along with TTIP4, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
58
59
TGND4
TRing5
Digital Ground. Transmitters 4.
Transmitter 5 Negative Bipolar Output.
Channel 5 within the XRT5997 device will use this pin, along with TTIP5, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
60
TVDD5
Positive Supply (+3.3V ± 5%), Transmitters 5.
61
TTIP5
Transmitter 5 Positive Bipolar Output.
Channel 5 within the XRT5997 device will use this pin, along with TRing5, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
62
63
TGND5
RTIP5
Digital Ground. Transmitters 5.
I
I
Receiver 5 Positive Bipolar Input.
The Receive Section of Channel 5 uses this input pin, along with RRing5 to
receive the bipolar line signal from the “Remote E1 Terminal”.
Receiver 5 Negative Bipolar Input.
64
RRing5
The Receive Section of Channel 5 uses this input pin, along with RTIP5 to
receive the bipolar line signal from the “Remote E1 Terminal”.
65
66
67
68
AVDD
AGND
AVDD
RRing7
Positive Supply (+3.3V ± 5%). Analog Circuitry.
AnalogGround.
Positive Supply (+3.3V ± 5%). Receiver 4, 6, 7.
I
Receiver 7 Negative Bipolar Input.
The Receive Section of Channel 7 uses this input pin, along with RTIP7 to
receive the bipolar line signal from the “Remote E1 Terminal”.
Rev. 1.0.0
11
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
69
RTIP7
I
Receiver 7 Positive Bipolar Input:
The Receive Section of Channel 7 uses this input pin, along with RRing7 to
receive the bipolar line signal from the “Remote E1 Terminal”.
70
71
RRing6
RTIP6
I
I
Receiver 6 Negative Bipolar Input:
The Receive Section of Channel 6 uses this input pin, along with RTIP6 to
receive the bipolar line signal from the “Remote E1 Terminal”.
Receiver 6 Positive Bipolar Input:
The Receive Section of Channel 6 uses this input pin, along with RRing6 to
receive the bipolar line signal from the “Remote E1 Terminal”.
72
73
74
AGND
DGND3
RxNEG6
Analog Ground. Receiver 4, 6, 7.
Digital Ground. Digital Circuitry.
O
O
Receiver 6 Negative Data Out:
This output pin will pulse “high” whenever Channel 6, within the XRT5997
device has received a “Negative Polarity” pulse, in the incoming line signal,
at RTIP6/RRing6 inputs.
75
RxPOS6
Receiver 6 Positive Data Out:
This output pin will pulse “high” whenever Channel 6, within the XRT5997
device has received a “Positive Polarity” pulse, in the incoming line signal, at
RTIP6/RRing6 inputs.
76
77
LOS6
O
I
Receiver 6 Loss of Signal:
This output pin toggles “high” if Channel 6, within the XRT5997 device has
detected a “Loss of Signal” condition in the incoming line signal.
Transmitter - Positive Data Input – Channel 6:
TxPOS6
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 6) in
the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “positive-polarity”
pulse onto the line via TTIP6 and TRing6 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk6 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “positive-polarity” pulse onto the line
via TTIP6 and TRing6 output pins.
Rev. 1.0.0
12
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
78
TxNEG6
I
Transmitter - Negative Data Input – Channel 6:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of the Channel 6)
in the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “negative-polarity”
pulse onto the line via TTIP6 and TRing6 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk6 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “negative-polarity” pulse onto the
line via TIP6 and TRing6 output pins.
79
TxClk6
I
Transmitter Clock Input – Channel 6:
If the user operates Channel 6 (within the XRT5997 device) in the “clocked”
mode, then the “Transmit Section” of the Channel 6 will use the falling edge of
this signal to sample the data at the TxPOS6 and TxNEG6 input pins.
Note: If the user operates the Channel 6 in the “clockless” mode, then the
Terminal Equipment should not apply a clock signal to this input pin.
80
81
TGND6
TTIP6
Digital Ground. Transmitters 6.
O
O
Transmitter 6 Positive Bipolar Output:
Channel 6 within the XRT5997 device will use this pin, along with TRing6, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
82
83
TVDD6
TRing6
Positive Supply (+3.3V ± 5%), Transmitters 6.
Transmitter 6 Negative Bipolar Output:
Channel 6 within the XRT5997 device will use this pin, along with TTIP6, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
84
DGND
Digital Ground. Digital Circuitry.
Rev. 1.0.0
13
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
Symbol
Type
Description
85
TxPOS7
I
Transmitter - Positive Data Input – Channel 7:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 7) in
the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “positive-polarity”
pulse onto the line via TTIP7 and TRing7 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk7 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “positive-polarity” pulse onto the line
via TTIP7 and TRing7 output pins.
86
87
TxNEG7
TxClk7
I
I
Transmitter - Negative Data Input – Channel 7:
Transmitter Clock Input – Channel 7:
If the user operates Channel 7 (within the XRT5997 device) in the “clocked”
mode, then the “Transmit Section” of the Channel 7 will use the falling edge of
this signal to sample the data at the TxPOS7 and TxNEG7 input pins.
Note: If the user operates the Channel 7 in the “clockless” mode, then the
Terminal Equipment should not apply a clock signal to this input pin.
88
89
DGND
TTIP7
Digital Ground: Digital Circuitry.
O
O
O
Transmitter 7 Positive Bipolar Output:
Channel 7 within the XRT5997 device will use this pin, along with TRing7, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
90
91
TVDD7
TRing7
Positive Supply: (+3.3V ± 5%), Transmitters 7.
Transmitter 7 Negative Bipolar Output:
Channel 7 within the XRT5997 device will use this pin, along with TTIP7, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
92
93
TGND7
TRing1
Digital Ground: Transmitters 7.
Transmitter 1 Negative Bipolar Output:
Channel 1 within the XRT5997 device will use this pin, along with TTIP1, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
94
TVDD1
Positive Supply (+3.3V ± 5%), Transmitters 1.
Rev. 1.0.0
14
XRT5997
PINDESCRIPTION(CONT'D)
Pin#
95
Symbol
TTIP1
Type
O
Description
Transmitter 1 Positive Bipolar Output.
Channel 1 within the XRT5997 device will use this pin, along with TRing1, to
transmit a bipolar line signal, via a 1:2 step-up transformer.
96
97
TGND1
TxClk1
Digital Ground. Transmitters 1.
I
Transmitter Clock Input – Channel 1:
If the user operates Channel 1 (within the XRT5997 device) in the “clocked”
mode, then the “Transmit Section” of the Channel 1 will use the falling edge of
this signal to sample the data at the TxPOS1 and TxNEG1 input pins.
Note: If the user operates the Channel 1 in the “clockless” mode, then the
Terminal Equipment should not apply a clock signal to this input pin..
98
TxNEG1
I
Transmitter - Negative Data Input – Channel 1:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of the Channel 1)
in the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “negative-polarity”
pulse onto the line via TTIP1 and TRing1 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk1 signal.
Clockless Mode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “negative-polarity” pulse onto the
line via TTIP1 and TRing1 output pins.
99
TxPOS1
I
Transmitter - Positive Data Input – Channel 1:
The exact signal that should be applied to this input pin depends upon
whether the user intends to operate the “Transmit Section” (of Channel 1) in
the “Clocked” or “Clockless” Mode.
ClockedMode:
The Terminal Equipment should apply bit-wide NRZ pulses on this input pin,
whenever the Terminal Equipment needs to transmit a “positive-polarity”
pulse onto the line via TTIP1 and TRing1 output pins. The XRT5997
device will sample this input pin upon the falling edge of the TClk1 signal.
ClocklessMode:
The Terminal Equipment should apply RZ pulses to this input pin, anytime the
Terminal Equipment needs to transmit a “positive-polarity” pulse onto the line
via TTIP1 and TRing1 output pins.
100
LOS1
O
Receiver 1 Loss of Signal:
This output pin toggles “high” if Channel 1, within the XRT5997 device has
detected a “Loss of Signal” condition in the incoming line signal.
Rev. 1.0.0
15
XRT5997
RECEIVERELECTRICALCHARACTERISTICS
Unless otherwise specified: TA=-40 to 85°C, VDD=3.3V±5%, unless otherwise specified.
Parameter
Min
Typ
Max
Unit
TestConditions
Receiver Loss of Signal:
Threshold to Assert
12
20
-
dB
Cable attenuation @ 1024KHz
Threshold to Clear
Time Delay
11
10
-
15
-
dB
bit
255
Per ITU-G.775
Hysteresis
5
-
-
dB
dB
Receiver Sensitivity
11
13
Below nominal pulse amplitude of 3.0V
for 120Ω and 2.37V for 75Ω applications.
With -18dB interference signal added.
Interference Margin
Input Impedance
Jitter Tolerance:
20Hz
-18
5
-14
-
-
-
dB
With 6dB cable loss.
KΩ
10
5
700Hz
-
-
UIpp
10KHz —100KHz
Return Loss:
0.3
51KHz —102KHz
102KHz—2048KHz
2048KHz—3072KHz
14
20
16
-
-
-
-
-
-
dB
dB
dB
Per ITU-G.703
TRANSMITTER ELECTRICALCHARACTERISTICS
Unless otherwise specified: TA=-40 to 85°C, VDD=3.3V±5%, unless otherwise specified.
Parameter
Min
Typ
Max
Unit
TestConditions
AMIOutputPulseAmplitude:
75Ω Application
120Ω Application
2.13
2.70
2.37
3.0
2.60
3.30
V
V
Use transformer with 1:2 ratio and 9.1Ω
resistor in series with each end of primary.
Output Pulse Width
224
244
264
ns
Output Pulse Width Ratio
0.95
0.95
−
−
1.05
1.05
−
−
Per ITU-G.703
Per ITU-G.703
Output Pulse Amplitude Ratio
Output Return Loss:
51KHz —102KHz
102KHz—2048KHz
2048KHz—3072KHz
10
16
12
-
-
-
-
-
-
dB
dB
dB
Per ETSI 300 166 and CH PTT
Rev. 1.0.0
16
XRT5997
269ns
244+50
V= 100 %
194ns
244-50
Normal Pulse
50 %
244 ns
219 ns
244-25
0 %
20 %
244 ns
244+244
Figure E1. ITU G.703 Pulse Template for Transmitter Output
DCELECTRICALCHARACTERISTICS
TA=-25°C, VDD=3.3V±5%, unless otherwise specified.
Parameter
Symbol
Min
Typ
3.3
Max
Unit
Power Supply Voltage
VDD
3.13
3.46
V
Input High Voltage
Input Low Voltage
VIH
VIL
2.0
-0.5
-
-
5.0
0.8
V
V
Output High Voltage @
IOH=-5mA
VOH
2.4
-
-
V
Output Low Voltage @
IOL=5mA
Input Leakage Current
(except Input pins w/ pull-up resistor.)
Input Capacitance
VOL
IL
-
-
-
-
0.4
± 10
V
µA
CI
CL
5.0
-
pF
pF
Output Load Capacitance
-
25
Rev. 1.0.0
17
XRT5997
ACELECTRICALCHARACTERISTICS
TA=-25°C, VDD=3.3V±5%, unless otherwise specified.
Parameter
Symbol
T1
Min
-
Typ
488
50
-
Max
Unit
ns
TCLK Clock Period
-
53
-
TCLK Duty Cycle
T2
47
50
30
%
Transmit Data Setup Time
Transmit Data Hold Time
Transmit Data Prop. Delay Time
- RZ data Mode
TSU
THO
T3
ns
-
-
ns
-
30
30
-
-
-
ns
ns
ns
ns
ns
ns
ns
ns
- NRZ data Mode (clock mode)
TCLK Rise Time(10%/90%)
TCLK Fall Time(90%/10%)
Receive Data Rise Time
Receive Data Fall Time
Receive Data Prop. Delay
Receive Data Pulse Width
-
TR
TF
-
40
40
40
40
-
-
-
Rtr
-
-
Rtf
-
-
-
Rpd
Rxpw
75
244
200
350
Per channel power consumption including the line power dissipation, tranmission and receive paths
all active: TA=-40 to 85°C, VDD=3.3V±5%, unless otherwise specified.
Parameter
Symbol
Min
Typ
Max Unit
Conditions
Power Consumption
Power Consumption
Power Consumption
PC
PC
PC
-
-
-
85
72
135
95
80
144
mW
mW
mW
75Ω load, operating at 50% Mark Density.
120Ω load, operating at 50% Mark Density.
75Ω load, operating at 100% Mark Density.
Power Consumption
Power Consumption
PC
PC
-
-
106
16
115
18
mW
mW
120Ω load, operating at 100% Mark Density.
Transmitter in Powered-down mode.
ABSOLUTEMAXIMUMRATINGS
StorageTemperature
OperatingTemperature
-65°C to + 150°C
-40°C to + 85°C
ESD Rating
>4000V on all pins2
Supply Voltage
-0.5V to + 6.0V
2
Note: Human Body Model, 100pF capacitor discharged through a 1.5KΩ resistor.
Rev. 1.0.0
18
XRT5997
1.1
The Transmit Input Interface
SYSTEMDESCRIPTION
The XRT5997 device is a Seven (7) channel E1
transceiver that provides an electrical interface for
2.048Mbpsapplications. Eachofthesevenchannels
includesareceivecircuitthatconvertsanITU-TG.703
compliant bipolar signal into a TTL compatible logic
levels. Each receiver also includes an LOS (Loss of
Signal) detection circuit. Similarly, in the Transmit
Direction, each Transmitter converts TTL compatible
logic levels into a G.703 compatible bipolar signal.
TheTransmittermaybeoperatedineithera“Clocked”
or “Clockless” Mode.
The Transmit Input Interface accepts either “clocked”
or “clockless” data from the Terminal Equipment. The
manner in how the Terminal Equipment should apply
data to a given channel within the XRT5997 device
dependsuponwhetherthechannelisbeingoperatedin
the “clocked” or “clockless” mode.
1.2.1 Operating the Transmitter in the Clocked
Mode
The user can configure a given channel (within the
XRT5997device)tooperateinthe“Clocked”modeby
simply applying a 2.048MHz clock signal to the
“TxClk_x” input pin (where x denotes a given channel
within the XR5997 device). The XRT5997 device
contains some circuitry that sense activity on the
“TxClk_x” line. If this circuit senses activity on the
“TxClk_x” line, then the corresponding channel will
automatically be operating in the “Clocked” Mode.
EachchannelwithintheXRT5997LIUdeviceconsists
of both a Transmit Section and a Receive Section,
each of these sections will be discussed in detail
below.
1.0 The Transmit Section
In general, the purpose of the “Transmit Section”
(within each channel of the XRT5997 device) is to
acceptTTL/CMOSleveldigitaldata(fromtheTerminal
Equipment), and to encode it into a format such that it
can:
In the Clocked Mode, the Terminal Equipment is
expected to apply a 2.048MHz clock signal at the
TxClk_x input pin and NRZ data at the TxPOS_x and
TxNEG_x input pins. The “Transmit Input Interface”
circuit will sample the data, at the TxPOS_x and
TxNEG_xinputpins,uponthefallingedgeofTxClk_x,
as illustrated in Figure 3.
1. Beefficientlytransmittedovercoaxial-ortwisted-
pair cable at the E1 data rate; and
2. Be reliably received by the Remote Terminal
Equipment at the other end of the E1 data link.
3. Comply with the ITU-T G.703 pulse template
requirements, for E1 applications.
The circuitry that the Transmit Section (within the
XRT5997 device) uses to accomplish this goal is
discussed below. The Transmit Section of the
XRT5997 device consists of the following blocks:
• Transmit Input Interface
• Pulse Shaping Block
Rev. 1.0.0
19
XRT5997
tSU
tHO
TxPOS_x
TxNEG_x
TClk_x
Figure 2. Illustration on how the XRT5997 Device Samples the data on
the TxPOS_x and TxNEG_x input pins
Ingeneral, iftheXRT5997devicesamplesa“1”onthe
1.2.1 Operating the Transmitter in the
“Clockless”Mode
TxPOS_x input pin, then the “Transmit Section” of the
devicewillultimatelygenerateapositivepolaritypulse
via the TTIP_x and TRing_x output pins (across a 1:2
transformer). Conversely, if the XRT5997 device
samples a “1” on the “TxNEG_x” input pin, then the
“Transmit Section” of the device will ultimately gener-
ateanegativepolaritypulseviatheTTIP_xandTRing_x
output pins (across a 1:2 transformer).
The user can configure a given channel (within the
XRT5997device)tooperateinthe“Clockless”modeby
doingthefollowing:
•
•
Not applying a clock signal to the TxClk_x input,
and either pulling this pin to VDD or letting it float.
By applying RZ (Return to Zero) data to the
TxPOS_xandTxNEG_xinputpins, asillustrated
below.
Rev. 1.0.0
20
XRT5997
RZ Pulse is to be
applied in the first
half of the bit-period
No pulse is to be applied
in the second half of the
bit period
Bit
Period
Data
1
1
0
1
1
0
1
TxPOS _x
TxNEG _x
TxClk _x
No Activity in TxClk Line
Figure 3. Illustration on how the Terminal Equipment should apply data to the “Transmit Section” of a
given Channel (within the XRT5997 Device), when operating in the “Clockless” Mode
Figure 3, indicates that when the user is operating a
channelinthe“Clockless”Mode, thenthecorrespond-
ing Terminal Equipment must do the following:
1.3 The Pulse Shaping Circuit
Thepurposeofthe“TransmitPulseShaping”circuitis
togenerate“TransmitOutput”pulsesthatcomplywith
theITU-TG.703PulseTemplateRequirementsforE1
Applications.
•
•
Not apply a signal on the “TxClk_x” line.
Whenapplyingapulse(toeithertheTxPOS_xor
TxNEG_x input pin), apply an RZ pulse to the
appropriate input pin. This RZ pulse should only
have a width of one-half the bit-period. Addition,
the RZ pulse should occupy only the first half of
thebit-period. TheTxPOS_xandTxNEG_xinput
pins must be at 0V, during the second half of
everybit-period.
Rev. 1.0.0
21
XRT5997
269ns
(244 + 25)
194ns
V = 100%
Nominal Pulse
50%
244ns
219ns
(244 - 25)
10%
0%
10%
20%
Figure 4. Illustration of the ITU-T G.703 Pulse Template for E1 Applications
Asaconsequence,eachchannel(withintheXRT5997
device) will take each mark (which is provided to it via
the “Transmit Input Interface” block, and will generate
a pulse that complies with the pulse template, pre-
sentedinFigure4,(whenmeasuredonthesecondary-
side of the Transmit Output Transformer).
However, inbothapplications(e.g., 75Ω or120Ω), the
userisadvisedtointerfacetheTransmittertotheLine,
in the manner as depicted in Figures 5 and 6, respec-
tively.
1.4 Interfacing the Transmit Sections of the
XRT5997 device to the Line
ITU-T G.703 specifies that the E1 line signal can be
transmittedovercoaxialcableandterminatedwith75Ω
or transmitted over twisted-pair and terminated with
120Ω.
Rev. 1.0.0
22
XRT5997
U1
99
98
97
TxPOS_1
TxPOS_1
R1
95
1
2
J1
TTIP_1
9.1
BNC
1:2
1
4
5
8
1
TxNEG_1
TxNEG_1
PE-65835
R2
93
1
2
TRING_1
9.1
TxLineClk_1
TxCLK_1
XRT5997
Figure 5. Illustration of how to interface the Transmit Sections of the
XRT5997 device to the Line (for “75Ω ” Applications)
U1
99
TxPOS_1
TxPOS_1
R1
9.1
95
1
2
TTIP_1
1:2
1
4
5
8
TTIP_Channel_1
TRing_Channel_1
98
TxNEG_1
TxNEG_1
PE-65835
R2
9.1
93
1
2
TRing_1
97
TxLineClk_1
TxClk_1
XRT5997
Figure 6. Illustration of how to interface the Transmit Sections the
XRT5997 device to the Line (for “120Ω ” Applications)
Notes:
1. Figures 5 and 6, indicate that for both “75Ω” and
“120Ω” applications, the user should connect a 9.1Ω
resistor, in series, between the TTIP/TRing outputs
and the transformers.
2. Figure 5 and 6, indicate that the user should use a “1:2
STEP-UP” Transformer.
Rev. 1.0.0
23
XRT5997
Transmit Transformer Recommendations
Parameter
Value
Turns Ratio
1:2
Primary Inductance
Isolation Voltage
Leakage Inductance
The following Transformers are Recommended for Use
Part Number
PE-65835
Vendor
Pulse
Isolation
Package Type
TTI 7154-R
TG26-1205
Transpower Technologies, Inc.
HALO
Note: More transformers will be added to this list as we
take the time to evaluate these transformers.
Magnetic Supplier Information
Pulse
TranspowerTechnologies
CorporateOffice
CorporateOffice
12220WorldTradeDrive
San Diego, CA 92128
Tel:(619)-674-8100
FAX:(619)-674-8262
9410 Prototype Drive, Ste #1
Reno, NV89511
Tel:(800)511-7308or
(775)852-0140
Fax:(775)852-0145
www.trans-power.com
Europe
1 & 2 Huxley Road
The Surrey Research Park
Guildford, Surrey GU2 5RE
UnitedKingdom
HALOElectronics
P.O. Box 5826
Redwood City, CA 94063
Tel: (650)568-5800
FAX: (650)568-6161
Tel: 44-1483-401700
FAX: 44-1483-401701
Asia
150KampongAmpat
#07-01/02
KA Centre
Singapore368324
Tel:65-287-8998
FAX:65-280-0080
Rev. 1.0.0
24
XRT5997
2.0 TheReceiveSection
2.1 Interfacing the Receive Sections to the Line
TheReceiveSectionsoftheXRT5997deviceconsists
of the following blocks:
The design of each channel (within the XRT5997
device) permits the user to transformer-couple or
capacitive-couple the Receive Section to the line.
Additionally, as mentioned earlier, the specification
documentsforE1specify75Ω terminationloads,when
transmittingovercoaxialcable,and120Ωloads,when
transmitting over twisted-pair. Figures 7 , through 9
present the various methods that the user can employ
in order to interface the Receivers (of the XRT5997
device) to the line.
• The “Receive Equalizer” block
• The “Peak Detector” and “Slicer” block
• The “LOS Detector” block
• The “Receive Output Interface” block
U1
1
7
RxPOS_1
RxPOS_1
RxNEG_1
RTIP_1
J1
BNC
1:2
1
4
5
1
R1
2
18.7
RxNEG_1
8
PE-65835
100
8
Loss of Signal - 1
RxLOS_1
RRing_1
XRT5997
Figure 7. Recommended Schematic for Interfacing the Receive Sections of the XRT5997
Device to the Line for 75Ω Applications (Transformer-Coupling)
Rev. 1.0.0
25
XRT5997
U1
1
7
RxPOS_1
RxPOS_1
RTIP_1
1:2
1
4
5
8
RTIP_1
R1
2
30.1
RxNEG_1
RxNEG_1
RRing_1
PE-65835
100
8
Loss of Signal - 1
RxLOS_1
RRing_1
XRT5997
Figure 8. Recommended Schematic for Interfacing the Receive Sections of the XRT5997
Device to the Line for 120Ω Applications (Transformer-Coupling)
Note:
Figures 7 and 8 indicate that the user should use a “2:1
STEP-DOWN” transformer, when interfacing the
receiver to the line.
Transmit Transformer Recommendations
Parameter
Value
Turns Ratio
1:2
Primary Inductance
Isolation Voltage
Leakage Inductance
The following Transformers are Recommended for Use
Part Number
PE-65835
Vendor
Pulse
Isolation
Package Type
TTI 7154-R
TG26-1205
Transpower Technologies, Inc.
HALO
Note: More transformers will be added to this list as we
take the time to evaluate these transformers.
Rev. 1.0.0
26
XRT5997
Capacitive-Coupling the Receiver to the Line
Figure 9, presents a recommended approach that the
user to employ when capacitive-coupling the Receive
Section to the line.
U1
J1
C1
BNC
R1
1
7
1
2
1
2
1
RxPOS_1
RxNEG_1
RxPOS_1
RxNEG_1
RTIP_1
37.4
0.1uF
2
R2
37.4
C2
2
100
8
1
Loss of Signal - 1
RxLOS_1
RRing_1
0.1uF
XRT5997
Figure 9. Recommended Schematic for Interfacing the Receive Sections of the XRT5997 Device to
the Line for 75Ω Applications(Capacitive-Coupling)
2.2 The “Receive Equalizer” Bock
AfteragivenChannel(withintheXRT5997device)has
received the incoming line signal, via the RTIP_x and
RRing_x input pins, the first block that this signal will
pass through is the Receive Equalizer block.
frequency components. If this line signal travels over
reasonably long cable lengths, then the shape of the
pulses (which were originally square) will be distorted
and with inter-symbol interference increases.
Asthelinesignalistransmittedfromagiven“Transmit-
ting” terminal, the pulse shapes (at that location) are
basically “square”. Hence, these pulses consist of a
combination of “low” and “high” frequency Fourier
components. As this line signal travels from the
“transmittingterminal”(viathecoaxialcableortwisted
pair) to the receiving terminal, it will be subjected to
“frequency-dependent”loss. Inotherwords,thehigher
The purpose of this block is to equalize the incoming
distorted signal, due to cable loss. In essence, the
ReceiveEqualizerblockaccomplishesthisbysubject-
ing the received line signal to “frequency-dependent”
amplification (which attempts to counter the fre-
quency-dependentlossthatthelinesignalhasexperi-
enced). By doing this, the Receive Equalizer is
attemptingtorestoretheshapeofthelinesignalsothat
the received data can be recovered reliably.
frequency components of the signal will be subjected
to a greater amount of attenuation than the lower
Rev. 1.0.0
27
XRT5997
2.3 The “Peak Detector and Slicer Block
withthe“LOSDeclaration/Clearance”requirementsper
ITU-T G.775. As a consequence, the channel will
declare an LOS Condition, (by driving the “RxLOS”
output pin “high”) if the received line signal amplitude
dropsto–20dBorbelow. Further,thechannelwillclear
theLOSConditionifthesignalamplituderisesbackup
to –15dB or above. Figure 10 presents an illustration
that depicts the signal levels at which a given channel
(withintheXRT5997device)willassertandclearLOS.
After the incoming line signal has passed through the
Receive Equalizer block, it will next be routed to the
“Slicer” block. The purpose of the “Slicer” block is to
quantifyagivenbit-period(orsymbol)withintheincom-
ing line signal as either a “1” or a “0”.
2.3 The “LOS Detector” block
The LOS Detector block, within each channel (of the
XRT5997device)wasspecificallydesignedtocomply
0 dB
Maximum Cable Loss for E1
LOS Signal Must be Cleared
-6 dB
-9dB
LOS Signal may be Cleared or Declared
-35dB
LOS Signal Must be Declared
Figure 10. Illustration of the Signal Levels that the Receiver Sections
(within XRT5997 device) will declare and clear LOS
Timing Requirements associated with Declaring and
theXRT5997devicewillcleartheLOSindicatorwithin
10 to 255 UI after restoration of the incoming line
signal. Figure 11 illustrates the LOS Declaration and
Clearance behavior, in response to first, the “Loss of
Signal” event and then afterwards, the restoration of
the signal.
ClearingtheLOSIndicator. TheXRT5997devicewas
designedtomeettheITU-TG.775specificationtiming
requirementsfordeclaringandclearingtheLOSindica-
tor. In particular, the XRT5997 device will declare an
LOS, between 10 and 255 UI (or E1 bit-periods) after
the actual time the LOS condition occurred. Further,
Rev. 1.0.0
28
XRT5997
Line Signal
is Restored
Actual O ccurrence
of LO S Condition
RxIN
Tim e Range for
LO S Declaration
255
UI
10 UI
255 UI
10 UI
LO S O utput Pin
0 UI
0 UI
G .775 Com pliance
Note: For E1, 1 UI = 488ns
Tim e Range for
LO S Clearance
G .775 Com pliance
Figure 11. The Behavior of the LOS Output Indicator, in response to
the Loss of Signal, and the Restoration of the Signal
2.3 The“ReceiveOutputInterface”block
Thepurposeofthe“ReceiveOutputInterface”blockis
tointerfacedirectlywiththe“ReceivingTerminalEquip-
ment”. The “Receive Output Interface” block outputs
thedata(whichhasbeenrecoveredfromtheincoming
linesignal)tothe“ReceiveTerminalEquipment”viathe
“RxPOS_x and RxNEG_x output pins.
Note: The “Receive Output Interface” block does not
supply a recovered clock. This device is intended to be
used in those applications, where the “Clock Recovery”
circuit is realized in an ASIC solution.
3.0 Shutting off the Transmitter
Eachchannel(withintheXRT5997device)permitsthe
user to shut off the “Transmit Driver” within their
respective “Transmit Section”. This feature can come
inhandyforsystemredundancydesignconsiderations
orduringdiagnostictesting. Theusercanactivatethis
feature by either of the following ways.
If the “Receive Sections” of the XRT5997 device has
received a “Positive-Polarity” pulse, via the RTIP_x
and RRing_x input pins, then the Receive Output
Interface will output a pulse via the “RxPOS_x” output
pins.
Similarly, if the “Receive Sections” of the XRT5997
devicehasreceiveda“Negative-Polarity”pulse,viathe
RTIP_x and RRing_x input pins, then the Receive
Output Interface will output a pulse via the “RxNEG_x”
output pins.
Method 1:
Connect the Transmit Data input pins (e.g., TxPOS_x
and TxNEG_x) to a logic “1”; or allow them to float.
(These input pins have an internal “pull-up” resistor).
Method 2:
Connect the “TxClk_x” input pin to a logic “0” (e.g.,
GND)andcontinuetoapplydataviatheTxPOS_xand
TxNEG_x input pins.
Rev. 1.0.0
29
XRT5997
NRZ Mode (Clock Mode)
T
1
T
T
F
R
T
2
TClk
T
T
T
SU
HO
TxPO S or
TNEG
T
XPW
3
V
TxO UT
TTIP/
TRing
RZ Mode (None-Clock Mode)
TxPO S or
TNEG
T
XPW
T
3
V
TxO UT
TTIP/
TRing
Figure 12. Transmit Timing Diagram
RRing
/RTIP
Rp
Rxpw
d
RxPO S
RxNEG
Rtr
Rtf
Figure 13. Receive Timing Diagram
Rev. 1.0.0
30
XRT5997
APPLICATIONINFORMATION
Figures14,15and16,provideexampleschematicson
how to interface Channel 1 of the XRT5997 device to
the line, under the following conditions.
• Receiver is Transformer-coupled to a 75Ω
unbalancedline.
• Receiver is Transformer-coupled to a 120Ω
balancedline.
• Receiver is Capacitive-coupled to a 75Ω
unbalancedline.
·
U1
J1
BNC
1
R1
9.1
99
95
1
2
TxPOS_1
TxNEG_1
TxPOS_1
TxNEG_1
TxClk_1
TTIP_1
1:2
1
4
5
8
98
97
PE-65835
R2
9.1
93
1
2
TxLineClk_1
TRing_1
J2
BNC
1
1
2
7
RxPOS_1
RxNEG_1
RxPOS_1
RxNEG_1
RTIP_1
1:2
5
1
4
R3
18.7
8
PE-65835
100
8
Loss of Signal - 1
RxLOS_1
XRT5997
RRing_1
Figure 14. Illustration on how to interface Channel 1 (of the XRT5997 Device) to the Line
(Receiver is Transformer-coupled to a 75Ω unbalanced line)
Rev. 1.0.0
31
XRT5997
U1
R1
99
98
97
95
1
2
TxPOS_1
TxNEG_1
TxPOS_1
TTIP_1
9.1
1:2
1
4
5
8
TTIP_1
TxNEG_1
TxClk_1
TRing_1
PE-65835
R2
93
1
2
TxLineClk_1
Tring_1
9.1
1
2
7
RxPOS_1
RxNEG_1
RxPOS_1
RTIP_1
1:2
1
5
8
RTIP_1
R3
30.1
RxNEG_1
RxLOS_1
XRT5997
4
RRing_1
PE-65835
100
8
Loss of Signal - 1
RRing_1
Figure 15, Illustration on how to interface Channel 1 (of the XRT5997 Device) to the Line
(Receiver is Transformer-coupled to a 120Ω balanced line)
Rev. 1.0.0
32
XRT5997
U1
J1
BNC
1
R1
9.1
99
98
97
95
1
2
TxPOS_1
TxNEG_1
TxPOS_1
TTIP_1
1:2
1
4
5
8
TxNEG_1
TxClk_1
PE-65835
R2
9.1
93
1
1
2
TxLineClk_1
TRing_1
J2
BNC
1
C1
R3
2
1
2
7
2
1
RxPOS_1
RxNEG_1
RxPOS_1
RTIP_1
37.4
0.1uF
R4
RxNEG_1
RxLOS_1
XRT5997
37.4
C2
2
100
8
1
Loss of Signal - 1
RRing_1
0.1uF
Figure 16. Illustration on how to interface Channel 1 (of the XRT5997 Device) to the Line
(Receiver is Capacitive-coupled to a 75Ω unbalanced line)
Rev. 1.0.0
33
XRT5997
Rev. 1.0.0
34
XRT5997
Notes
Rev. 1.0.0
35
XRT5997
Notes
Rev. 1.0.0
36
XRT5997
NOTICE
EXARCorporationreservestherighttomakechangestotheproductscontainedinthispublicationinordertoimprove
design,performanceorreliability.EXARCorporationassumesnoresponsibilityfortheuseofanycircuitsdescribed
herein, conveysnolicenseunderanypatentorotherright, andmakesnorepresentationthatthecircuitsarefreeof
patentinfringement.Chartsandschedulescontainedhereinareonlyforillustrationpurposesandmayvarydepending
upon a user’s specific application. While the information in this publication has been carefully checked; no
responsibility, however, is assumed for in accuracies.
EXAR Corporation does not recommend the use of any of its products in life support applications where the failure
ormalfunctionoftheproductcanreasonablybeexpectedtocausefailureofthelifesupportsystemortosignificantly
affectitssafetyoreffectiveness.ProductsarenotauthorizedforuseinsuchapplicationsunlessEXARCorporation
receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the
user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the
circumstances.
Copyright1999EXARCorporation
DatasheetSeptember1999
Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.
Rev. 1.0.0
37
相关型号：
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XRT6164AIP-F
PCM Transceiver, 1-Func, T-1(DS1), CMOS, PDIP16, 0.300 INCH, GREEN, PLASTIC, DIP-16
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