EXAR XR-T5793IV

XR-T5793
...the analog plus
Quad E1
Line Interface Unit
company TM
June 1997-3
Individual Channel Loss of Signal Detection, Local
and Remote Digital Loopback
FEATURES
Meets CCITT G.703 Pulse Mask Template for
2.048Mbps (E1) Rates
Low Power, CMOS Technology
Over-Temperature Protection
Transmitter and Receiver Interfaces Can Be:
– Single Ended, 75Ω Capacitive or Transformer
Coupled
APPLICATIONS
– Balanced, 100Ω or 120Ω Transformer Coupled
Multi-Line E1 Interface Cards
Minimum Return Loss is 20dB (Receive) and 18dB
(Transmit), Exceeds G.703 and ETSI 300 166
Specifications
E1 Network Equipment
– Multiplexers
– Cross Connects
– Switching Systems
Bipolar Outputs Can Be Disabled Individually (High
Z Outputs)
Fault Tolerant Systems
System Interface is TTL Compatible on Digital Input
and TTL/CMOS Compatible on Digital Output Pins
GENERAL DESCRIPTION
sensitivity of 600mV over the operating temperature
range. Return loss on the receive interfaces is minimum
20dB from 51kHz to 3.072MHz.
The XR-T5793 is an optimized line interface unit, built
using low power CMOS technology. This device contains
four independent E1 channels for primary rate, PCM
applications up to 2.048Mbps. Each channel performs
the driver and receiver functions necessary to convert
bipolar signals to TTL/CMOS compatible logic levels and
vice versa. The device supports single ended or balanced
line interfaces on each channel, thereby providing the
user an option of reducing system cost and board space
by replacing the transformer with a capacitor.
Local and remote loopbacks can be performed on any of
the four channels. A separate loss of signal (LOS)
detection circuitry and a LOS pin is provided for each
input.
The XR-T5793 is targeted for multi-line E1 line card
applications where real estate and low power
consumption are critical. Also, the device may be used in
T1 applications (1.544Mbps) which do not require
meeting the DSX-1 cross connect pulse template. The
XR-T5793 is pin compatible with the XR-T5794, which
supports a fifth channel. The fifth channel is for
redundancy and dedicated monitoring on any of the eight
bipolar paths.
Each of the four drivers can be independently disabled,
allowing maximum flexibility in system power
management. Output pulses are fully CCITT G.703
compliant. Moreover, the return loss is at least 18dB over
a frequency range of 51kHz to 3.072MHz.
The slicing circuit in the receive path is able to tolerate a
maximum of 12dB of cable loss with a minimum input
ORDERING INFORMATION
Part No.
Package
Operating
Temperature Range
XR-T5793IJ
68 Lead PLCC
-40°C to +85°C
XR-T5793IV
80 Lead TQFP (14 x 14 x 1.4 mm)
-40°C to +85°C
Rev. 2.00
1995
EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 (510) 668-7000 FAX (510) 668-7017
1
XR-T5793
BLOCK DIAGRAM
Transceiver 1
Transceiver 2
75Ω Unbalanced
(Without Transformer) TIP
Transceiver 3
0.1µF
Impedance Selectable
Receivers. Return
Loss Exceeds G7.03.
Slicer
RXIN
100
or
120
PE-65834
TTI-7148
Peak
Detector
Slice
Voltage
E1/T1-
LOS Threshold Based on G.775
LOOPSEL (1.0)
LOOPEN
LPMOD
TXOUT
TIP
120Ω,100Ω or
75Ω Balanced TX OUTPUT
RING
Rout1
TXEN
PE-65839
TTI-7149
75Ω Unbalanced TIP
(Without Transformer)
LOS
Level
Detector
TIP
120Ω Balanced
(or 100Ω ) RX INPUT
RING
Impedance
Selectable
Tristate
Drivers Return
Loss Exceeds
ETSI 300 166
Transceiver 4
75
0.1µF
Driver
L
o
c
a
l
/
R
e
m
o
t
e
L
o
o
p
b
a
c
k
RXPOS
RXNEG
TXPOS
TXNEG
TCLK
ROUT1
Note
1R
OUT = 68Ω for 120Ω line impedance, ROUT = 62Ω for 100Ω line impedance, ROUT = 68Ω for 75Ω line impedance
Figure 1. Block Diagram
Rev. 2.00
2
XR-T5793
9
NC
AVDD
TXCLK4
TXPOS4
TXNEG4
TXCLK3
TXPOS3
TXNEG3
LOOPEN4
LOOPEN3
GND
VDD
RXPOS3
RXNEG3
RXPOS4
RXNEG4
RVDD
SS
SS
SS
TXEN3
TXEN4
TXOUT4
TVDD
TV
TXOUT3
AGND
TV DD
NC
TV
AGND
TXOUT2
TV
TVDD
TXOUT1
TXEN1
TXEN2
PIN CONFIGURATION
1
10
61
60
26
44
43
LPMOD4
LPMOD3
RXIN4
LOS4
LOS3
RXIN3
NC
NC
RGND
RGND
NC
RXIN2
LOS1
LOS2
RXIN1
LPMOD2
LPMOD1
27
LOSLVS
AVSS
TXCLK2
TXPOS2
TXNEG2
TXCLK1
TXPOS1
TXNEG1
LOOPEN2
LOOPEN1
E1/T1–
VSS
RXPOS2
RXNEG2
RXPOS1
RXNEG1
RVSS
LOSLVS
AVSS
AVSS
AVSS
TXCLK2
TXPOS2
TXNEG2
TXCLK1
TXPOS1
TXNEG1
LOOPEN2
LOOPEN1
E1/T1VSS
RXPOS2
RXNEG2
RXPOS1
RXNEG1
RVSS
RVSS
68 Lead PLCC
60
NC
NC
TXEN2
TXEN1
TXOUT1
TVDD
TVSS
TXOUT2
AGND
TVSS
NC
TVDD
AGND
TXOUT3
TVSS
TVDD
TXOUT4
TXEN4
TXEN3
NC
41
61
40
80
21
20
NC
NC
AVDD
AVDD
TXCLK4
TXPOS4
TXNEG4
TXCLK3
TXPOS3
TXNEG3
LOOPEN4
LOOPEN3
GND
V DD
RXPOS3
RXNEG3
RXPOS4
RXNEG4
RVDD
RV DD
1
80 Lead TQFP (14 x 14 x 1.4 mm)
Rev. 2.00
3
NC
NC
LPMOD1
LPMOD2
RXIN1
LOS2
LOS1
RXIN2
NC
RGND
RGND
RGND
NC
NC
RXIN3
LOS3
LOS4
RXIN4
LPMOD3
LPMOD4
XR-T5793
PIN DESCRIPTION
PLCC
Pin #
SQFP
Pin #
Symbol
1
71
NC
2
72
TVDD
VDD
Transmit VDD. 5V (5%).
3
73
AGND
GND
Analog Ground.
4
74
TXOUT3
O
5
75
TVSS
VSS
Transmit VSS. -5V (5%).
6
76
TVDD
VDD
Transmit VDD. +5V (5%).
7
77
TXOUT4
O
Transmitter 4 Output. Transmitter 4 bipolar output connected to coupling
capacitor or pulse transformer by a resistor.
8
78
TXEN4
I
Transmitter 4 Output Enable. If driven high the transmitter 4 output drivers
are enabled. Hi-Z otherwise.
9
79
TXEN3
I
Transmitter 3 Output Enable. If driven high the transmitter 3 output drivers
are enabled. Hi-Z otherwise.
10
1, 2, 80
NC
NC
No Connect.
11
3,4
AVDD
VDD
Analog VDD.
12
5
TXCLK4
I
Transmitter 4 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
13
6
TXPOS4
I
Transmitter 4 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 4.
14
7
TXNEG4
I
Transmitter 4 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 4.
15
8
TXCLK3
I
Transmitter 3 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
16
9
TXPOS3
I
Transmitter 3 Positive Data in. Positive data input in NRZ or RZ format for
transmitter 3.
17
10
TXNEG3
I
Transmitter 3 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 3.
18
11
LOOPEN4
I
Loop Enable 4. If driven high the specified loop type will be enabled for
channel 4. Otherwise normal operation will continue.
19
12
LOOPEN3
I
Loop Enable 3. If driven high the specified loop type will be enabled for
channel 3. Otherwise normal operation will continue.
20
13
GND
GND
Digital Ground.
21
14
VDD
VDD
Digital VDD. +5V (5%).
22
15
RXPOS3
O
Receiver 3 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 3.
23
16
RXNEG3
O
Receiver 3 Positive Data Out. Negative data output in NRZ or RZ format for
receiver 3.
24
17
RXPOS4
O
Receiver 4 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 4.
25
18
RXNEG4
O
Receiver 4 Positive Data Out. Negative data output in NRZ or RZ format for
receiver 4.
26
19,20
RVDD
VDD
Type
Description
No Connect.
Transmitter 3 Output. Transmitter 3 bipolar output connected to coupling
capacitor or pulse transformer by a resistor.
Receive VDD. +5V (5%).
Rev. 2.00
4
XR-T5793
PIN DESCRIPTION (CONT’D)
PLCC
Pin #
SQFP
Pin #
Symbol
Type
27
21
LPMOD4
I
Loop Mode 4. If driven high the loopback mode of channel 4 will be set to remote loop. Otherwise theloopback mode will remain at local loop. The
actualloopback will be activated when the LOOPEN4 is asserted.
28
22
LPMOD3
I
Loop Mode 3. If driven high the loopback mode of channel 3 will be set to remote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN3 is asserted.
29
23
RXIN4
I
Receiver 4 Input. Receiver 4 bipolar input connected to coupling capacitor or
pulse transformer.
30
24
LOS4
O
Receiver 4 Loss of Signal. Asserted during LOS condition. Clear otherwise.
31
25
LOS3
O
Receiver 3 Loss of Signal. Asserted during LOS condition. Clear otherwise.
32
26
RXIN3
I
Receiver 3 Input. Receiver 3 bipolar input connected to coupling capacitor or
pulse transformer.
33
27
NC
No Connect.
34
28
NC
No Connect.
35
29, 30
RGND
GND
Receive Ground.
36
31
RGND
GND
Receive Ground.
37
32
NC
38
33
RXIN2
I
Receiver 2 Input. Receiver 2 bipolar input connected to coupling capacitor or
pulse transformer.
39
34
LOS1
O
Receiver 1 Loss of Signal. Asserted during LOS condition. Clear otherwise.
40
35
LOS2
O
Receiver 2 Loss of Signal. Asserted during LOS condition. Clear otherwise.
41
36
RXIN1
I
Receiver 1 Input. Receiver 1 bipolar input connected to coupling capacitor or
pulse transformer.
42
37
LPMOD2
I
Loop Mode 2. If driven high the loopback mode of channel 2 will be set to remote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN2 is asserted.
43
38
LPMOD1
I
Loop Mode 1. If driven high the loopback mode of channel 1 will be set to remote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN1 is asserted.
-
39, 40
NC
NC
No Connect.
44
41,42
RVSS
VSS
Receive VSS. -5V (5%).
45
43
RXNEG1
O
Receiver 1 Negative Data Out. Negative data output in NRZ or RZ format for
receiver 1.
46
44
RXPOS1
O
Receiver 1 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 1.
47
45
RXNEG2
O
Receiver 2 Negative Data Out. Negative data output in NRZ or RZ format for
receiver 2.
48
46
RXPOS2
O
Receiver 2 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 2.
49
47
VSS
VSS
50
48
E1/T1-
I
Description
No Connect.
Digital VSS. -5V (5%).
E1/T1- Selection. Apply logic one to select the receive data threshold
appropriate for E1 operation. Connect to ground to select the T1 data
threshold.
Rev. 2.00
5
XR-T5793
PIN DESCRIPTION (CONT’D)
PLCC
Pin #
SQFP
Pin #
Symbol
Type
51
49
LOOPEN1
I
Loop Enable 1. If driven high the specified loopback mode will be enabled for
channel 1. Otherwise normal operation will continue.
52
50
LOOPEN2
I
Loop Enable 2. If driven high the specified loopback mode will be enabled for
channel 2. Otherwise normal operation will continue.
53
51
TXNEG1
I
Transmitter 1 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 1.
54
52
TXPOS1
I
Transmitter 1 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 1.
55
53
TXCLK1
I
Transmitter 1 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
56
54
TXNEG2
I
Transmitter 2 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 2.
57
55
TXPOS2
I
Transmitter 2 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 2.
58
56
TXCLK2
I
Transmitter 2 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
59
57,58,59
AVSS
VSS
60
60
LOSLVS
I
Description
Analog VSS.
Loss of Signal Voltage Select. Apply logic one to select LOS voltage level
appropriate for 120Ω balanced receiver operation. Connect to ground to
choose LOS voltage for 75Ω unbalanced operation.
-
61, 62
NC
NC
61
63
TXEN2
I
No Charge.
Transmitter 2 Output Enable. If asserted the transmitter 2 output drivers are
enabled. High-Z otherwise.
62
64
TXEN1
I
Transmitter 1 Output Enable. If asserted the transmitter 1 output drivers are
enabled. High-Z otherwise.
63
65
TXOUT1
O
Transmitter 1 Output. Transmitter 1 bipolar output connected to coupling
capacitor or pulse transformer through a resistor.
64
66
TVDD
VDD
Transmit VDD. +5V (5%).
65
67
TVSS
VSS
Transmit VSS. -5V (5%).
66
68
TXOUT2
O
67
69
AGND
GND
Analog Ground.
68
70
TVSS
VSS
Transmit VSS. –5V (5%).
Transmitter 2 Output. Transmitter 2 bipolar output connected to coupling
capacitor or pulse transformer through a resistor.
Rev. 2.00
6
XR-T5793
DC ELECTRICAL CHARACTERISTICS
Test Conditions: TA = -40°C to 25°C to 85°C, all VDDs = 5V 5%, all VSSs = -5V 5%, all GNDs = 0V
Symbol
Parameter
Min.
Typ.
Max.
Unit
Conditions
DC Parameters
VDDs
DC Supply Positive
4.75
5.00
5.25
V
VSSs
DC Supply Negative
-4.75
-5.00
-5.25
V
Inputs
VIH
High Level Input
VIL
Low Level Input
0.8
V
Input Pull Down Current
40
µA
IPDC
2.0
V
Outputs
VOH
High Level Output
3.5
V
IOH = -10µA
VOH
High Level Output
2.4
V
IOH = -40µA
VOL
Low Level Output
0.4
V
IOL = 1.6mA
Receiver Specifications
RXP
Receiver Sensitivity
0.6
4.2
Vp
RXCL
Allowed Cable Loss
0
10
12
dB
1.024MHz (E1)
(0dB=2.4V)
0
10
12
dB
772kHz (T1)
dB
with 6dB cable loss
RXIWT
RXTI
RXEI
RXLOS
RIN
Interference Margin (E1)
16
Receiver Slicing Level
(T1)1
60
65
70
%
Peak Voltage %
Receiver Slicing Level
(E1)1
45
50
55
%
Peak Voltage %
0.2
0.3
V
Receiver LOS Threshold
Input Resistance
2.5
kΩ
Up to 3.072MHz
Power Specifications (Without Monitor Channel)
PD
Power Dissipation
PD
Power Dissipation
PC
PC
PC
400
680
mW
250
280
mW
All Drivers in High-Z
Power Consumption
75Ω2
500
833
mW
All 1’s Transmit & Receive
Power Consumption
100Ω2
475
860
mW
All 1’s Transmit & Receive
Power Consumption
120Ω2
450
830
mW
All 1’s Transmit & Receive
PVDD
Power Supply Requirement
Pc/2
+5mW
mW
Pvss
Power Supply Requirement
Pc/2
- 5mW
mW
Notes
1 Selected by E1/T12 Power consumption = power dissipation + power to the cable.
Bold face parameters are covered by production test and guaranteed over operating temperature range.
Specifications are subject to change without notice
Rev. 2.00
7
XR-T5793
AC ELECTRICAL CHARACTERISTICS
Test Conditions: TA = -40°C to 25°C to 85°C, all VDDs = 5V 5%, all VSSs = -5V 5%, all GNDs = 0V
Symbol
Parameter
Min.
Typ.
Max.
Unit
Conditions
AC PARAMETERS
VTXOUT
Output Pulse Amplitude
(75Ω)
2.13
2.37
2.60
V
VTXOUT
Output Pulse Amplitude
(120Ω)
2.70
3.0
3.30
V
VTXOUT
Output Pulse Amplitude
(100Ω)
2.3
3.0
3.7
V
TXPW
Pulse Width (2.048MHz)
224
244
264
ns
Determined by TX Clock
TXPW
Pulse Width (1.544MHz)
274
324
374
ns
Determined by TX Clock
Pos/neg Pulse Imbalance
-5
+5
%
T1
TXCLK Clock Period (E1)
488
ns
T2
TXCLK Clock Period (T1)
648
ns
T3
TXCLK Duty Cycle
48
T4
Data Setup Time, TDATA to
TCLK
50
ns
T5
Data Hold Time, TCLK to TDATA
50
ns
TR
Clock Rise Time
30
ns
TF
Clock Fall Time
30
ns
T6
Receive Data High (E1)
269
ns
T7
Data Propagation Delay
100
ns
T 1 100
T2
ns
219
50
52
244
T1
T2
T8
Data Propagation Delay
%
0dB Cable Loss
Specifications are subject to change without notice
ABSOLUTE MAXIMUM RATINGS
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Storage Temperature . . . . . . . . . . . . -65°C to +150°C
Operating Temperature . . . . . . . . . . . . -40°C to +85°C
Rev. 2.00
8
XR-T5793
T1 or TF
T3
T3
TR
TXCLK(n)
T4
T5
TF
TXPOS(n)
TXNEG(n)
Figure 2. Transmit Timing Diagram
T7
T6
TR
RXIN
RXPOS
TF
T8
TF
RXNEG
T6
Figure 3. Receive Timing Diagram
Rev. 2.00
9
TR
XR-T5793
Transmit Interface
75Ω
100Ω
120Ω
Min.
Typ.
Min.
Typ.
Min.
Typ.
Units
51kHz to 102kHz
18
22
18
22
18
22
dB
102kHz to 2.048MHz
18
22
18
22
18
22
dB
2.048MHz to 3.072MHz
18
22
18
22
18
22
dB
Receive Interface
75Ω
100Ω
120Ω
Min.
Typ.
Min.
Typ.
Min.
Typ.
Units
51kHz to 102kHz
20
30
20
30
20
30
dB
102kHz to 2.048MHz
20
30
20
30
20
30
dB
2.048MHz to 3.072MHz
20
30
20
30
20
30
dB
Note
The return loss has been measured on the evaluation board coupled via a capacitor and terminated with 75Ω impedance.
Table 1. Return Loss Requirements (Resistor Tolerance: 1% on Transmit Side, 2% on Receive Side)
Turns Ratio
Line Impedance
RLOAD
Turns Ratio
Line Impedance
ROUT
1:1
75Ω
75Ω
1:1
75Ω
68Ω
1:1
120Ω
120Ω
1:1.265
120Ω
68Ω
1:1
100Ω
100Ω
1:1.265
100Ω
62Ω
Table 2. Input Transformer Requirements
Table 3. Output Transformer Requirements
Magnetic Supplier Information:
Transpower Technologies, Inc.
24 Highway 28, Suite 202
Crystal Bay, NV 89402–0187
Tel. (702) 831–0140
Fax. (702) 831–3521
Pulse
Telecom Product Group
P.O. Box 12235
San Diego, CA 92112
Tel. (619) 674-8100
Fax. (619) 674-8262
Rev. 2.00
10
XR-T5793
driver. External resistors are used to maintain an
accurate source impedance that has a high return loss to
the transformer or the capacitor. Each of the drivers can
be individually disabled, this is required in fault tolerant
applications where redundancy is a requirement. During
power-down mode of operation the bipolar outputs can be
disabled.
SYSTEM DESCRIPTION
This device is a quad E1 transceiver which provides
electrical interface for 2.048Mbps applications. Its unique
architecture includes four receiver circuits that convert
CCITT G.703 compliant bipolar signals to TTL compatible
logic levels. Likewise, in the other direction, four
transmitters translate TTL compatible logic levels to
G.703 compatible bipolar signals.
To protect the data integrity during a brownout, the output
pulse amplitudes are reduced by a factor of 25% if the
supply drops below an internally set limit.
This device supports two different types of loopback
functions. Each of four channels can be independently
looped either in local or remote sides digitally. The
remote loopback is performed between the receiver input
and transmitter output. To activate the remote loopback
on channel n, LOOPENn and LPMODn inputs are driven
high. Local loopback on channel n, can be established
similarly by driving LOOPENn high and clearing LPMODn
inputs.
More than one channel can be tested
simultaneously.
Transmission is possible either with or without a clock. If a
clock is used, the transmit input data must consist of
full-width NRZ pulses, and the transmitter output pulse
width is determined by the duty cycle of the clock. If the
transmit clock is tied high, the transmitter output pulses
are determined by the input data pulse width. In this
mode, RZ data must be supplied to the device.
RECEIVERS
TXP TXN
Each of the four identical E1 line receivers will accept
bipolar signals meeting the CCITT G.703 pulse mask
requirements. Each input stage consists of a slicing
circuitry which samples the incoming pulses at a fixed
percentage of the signals maximum amplitude. The
slicing voltage level is generated using a precision peak
detector. The receiver section can tolerate up to 12dB of
line loss (measured at 1.024MHz).
RXIN
RX
TX
TXOUT
LPMOD=0
LPEN=1
RXP RXN
Remote Loopback
TXP TXN
A loss of signal (LOS) is detected on any inputs by input
fail circuitry. There is an independent LOS pin dedicated
for each of the receivers. The LOS detection is based on
signal energy instead of number of zeros.
RXIN
RX
TX
LPMOD=0
LPEN=1
A balanced signal (100Ω or 120Ω) must be coupled by a
transformer. An unbalanced signal (75Ω) may be coupled
via capacitor or a transformer.
RXP RXN
Local Loopback
Figure 4. Loopback Configurations
TRANSMITTERS
This device contains four identical CCITT G.703
compliant transmitters which meet the return loss
requirements. Each transmitter is a single-ended voltage
Rev. 2.00
11
TXOUT
XR-T5793
Output Transformer Selection
3.
The 1:1.265 ratio output transformer is recommended for
the XR-T5793 because this ratio gives the best possible
transmitter output return loss for 120Ω balanced E1
service. However, other transformers may provide an
adequate return loss for many applications. The two
characteristics that determine series build-out resistor
requirements are:
R S + Req
4.
ǒVV
S
eq
*1
Ǔ
Now calculate the theoretical return loss.
Return Loss + 20 log
Driver output impedance is less than 5Ω.
)R
ǒReq
Ǔ
Req * R
S
S
Vs, which is the driver open circuit output voltage, is
4.5V peak.
The calculation given below uses the recommended
1:1.265 ratio transformer as an example:
The following method may be used to determine
transformer suitability for a given use.
1.
Calculate the source resistance, Rs.
Transformer Ratio = 1:1.265
VO = 3.0V Peak
RL = 120Ω
List the application requirements.
Transformer ratio = 1:n
VO = Peak output pulse amplitude
RL = Load resistance
Req +
RL
+ 120 + 75Ω
1.6
n2
Rs
1:n
V
Veq + no + 3.0 + 2.37V
1.265
1
3
VO
Vs
4
RL
2
Rs + Req
Figure 5. Equivalent Impedance Schematic
2.
V
ǒVeq
* 1 Ǔ + 75 ǒ 4.5 * 1 Ǔ + 67.4Ω
2.37
S
Calculate equivalent output voltage and load
resistance without the transformer.
R eq
R
+ 2L
n
V eq
(Datasheet specifies standard value of 68Ω)
Calculate the theoretical return loss to determine if the
transformer is acceptable.
V
+ nO
ǒ
Vs
Ǔ
Return Loss + 20 log 75 ) 67.4 + 25.5dB
75 * 67.4
Rs
Req
Veq
Figure 6. Equivalent Simplified Schematic
Rev. 2.00
12
XR-T5793
269 ns
(244 + 25)
Nominal pulse
20%
10%
V = 100%
194 ns
(244 – 50)
10%
20%
50%
244 ns
219 ns
(244 – 25)
10%
10%
0%
10%
20%
488 ns
(244 + 244)
Note: V corresponds to the nominal peak value
Figure 7. CCITT G.703 Pulse Template
Rev. 2.00
13
10%
XR-T5793
68 LEAD PLASTIC LEADED CHIP CARRIER
(PLCC)
Rev. 1.00
D
C
Seating Plane
D1
45° x H1
A2
45° x H2
2 1 68
B1
B
D
D2
D3
D1
e
R
D3
A1
A
INCHES
SYMBOL
MILLIMETERS
MIN
MAX
MIN
MAX
A
0.165
0.200
4.19
5.08
A1
0.090
0.130
2.29
3.30
A2
0.020
---.
0.51
---
B
0.013
0.021
0.33
0.53
B1
0.026
0.032
0.66
0.81
C
0.008
0.013
0.19
0.32
D
0.985
0.995
25.02
25.27
D1
0.950
0.958
24.13
24.33
D2
0.890
0.930
22.61
23.62
D3
e
0.800 typ.
0.050 BSC
20.32 typ.
1.27 BSC
H1
0.042
0.056
1.07
1.42
H2
0.042
0.048
1.07
1.22
R
0.025
0.045
0.64
1.14
Note: The control dimension is the inch column
Rev. 2.00
14
XR-T5793
80 LEAD THIN QUAD FLAT PACK
(14 x 14 x 1.4 mm, TQFP)
Rev. 3.00
D
D1
60
41
61
40
D1
80
21
1
20
A2
B
e
C
A
Seating Plane
α
A1
L
INCHES
SYMBOL
A
A1
A2
B
C
D
D1
e
L
α
MIN
MILLIMETERS
MAX
MIN
0.055
0.063
0.002
0.006
0.053
0.057
0.009
0.015
0.004
0.008
0.622
0.638
0.547
0.555
0.0256 BSC
0.018
0.030
1.40
0.05
1.35
0.22
0.09
15.80
13.90
0°
7°
1.60
0.15
1.45
0.38
0.20
16.20
14.10
0.65 BSC
0.45
0.75
0°
Note: The control dimension is the millimeter column
Rev. 2.00
15
MAX
7°
D
XR-T5793
NOTICE
EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are
free of patent infringement. Charts and schedules contained herein are only for illustration purposes and may vary
depending upon a user’s specific application. While the information in this publication has been carefully checked;
no responsibility, however, is assumed for inaccuracies.
EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or
malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly
affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation
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.
Copyright 1995 EXAR Corporation
Datasheet June 1997
Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.
Rev. 2.00
16