XRT5793IV-F [EXAR]
PCM Transceiver, 4-Func, CMOS, PQFP80, 14 X 14 MM, 1.4 MM HEIGHT, GREEN, TQFP-80;
| 型号： | XRT5793IV-F |
| 厂家： | 
EXAR CORPORATION |
| 描述： | PCM Transceiver, 4-Func, CMOS, PQFP80, 14 X 14 MM, 1.4 MM HEIGHT, GREEN, TQFP-80 PC 电信 电信集成电路 |
| 文件： | 总16页 (文件大小：160K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
XR-T5793
Quad E1
Line Interface Unit
...the analog plus companyTM
June 1997-3
FEATURES
D Individual Channel Loss of Signal Detection, Local
and Remote Digital Loopback
D Meets CCITT G.703 Pulse Mask Template for
D Low Power, CMOS Technology
D Over-Temperature Protection
2.048Mbps (E1) Rates
D Transmitter and Receiver Interfaces Can Be:
– Single Ended, 75Ω Capacitive or Transformer
APPLICATIONS
Coupled
– Balanced, 100Ω or 120Ω Transformer Coupled
D Multi-Line E1 Interface Cards
D Minimum Return Loss is 20dB (Receive) and 18dB
(Transmit), Exceeds G.703 and ETSI 300 166
Specifications
D E1 Network Equipment
– Multiplexers
– Cross Connects
– Switching Systems
D Bipolar Outputs Can Be Disabled Individually (High
Z Outputs)
D Fault Tolerant Systems
D System Interface is TTL Compatible on Digital Input
and TTL/CMOS Compatible on Digital Output Pins
GENERAL DESCRIPTION
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.
sensitivity of 600mV over the operating temperature
range. Return loss on the receive interfaces is minimum
20dB from 51kHz to 3.072MHz.
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
Operating
Temperature Range
Part No.
Package
68 Lead PLCC
80 Lead TQFP (14 x 14 x 1.4 mm)
XR-T5793IJ
XR-T5793IV
-40°C to +85°C
-40°C to +85°C
Rev. 2.00
E1995
EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 z (510) 668-7000 z FAX (510) 668-7017
1
XR-T5793
BLOCK DIAGRAM
Transceiver 1
Transceiver 2
Transceiver 3
75Ω Unbalanced
(Without Transformer)
TIP
TIP
0.1µF
Transceiver 4
LOS
75
Impedance Selectable
Receivers. Return
Loss Exceeds G7.03.
Level
Detector
L
Slicer
RXPOS
RXNEG
RXIN
o
c
a
l
120Ω Balanced
RX INPUT
RING
(or 100Ω )
100
or
120
Peak
Detector
Slice
Voltage
/
Impedance
Selectable
PE-65834
TTI-7148
R
e
m
o
t
E1/T1-
Tristate
Drivers Return
Loss Exceeds
ETSI 300 166
LOS Threshold Based on G.775
LOOPSEL (1.0)
LOOPEN
e
LPMOD
L
o
o
p
b
a
c
k
TXPOS
TXNEG
TCLK
TXOUT
Driver
TIP
120Ω,100Ω or
75Ω Balanced
1
Rout
TX OUTPUT
RING
TXEN
PE-65839
TTI-7149
75Ω Unbalanced
(Without Transformer)
TIP
1
R
OUT
0.1µF
Note
1
R
= 68Ω for 120Ω line impedance, R
= 62Ω for 100Ω line impedance, R
= 68Ω for 75Ω line impedance
OUT
OUT
OUT
Figure 1. Block Diagram
Rev. 2.00
2
XR-T5793
PIN CONFIGURATION
9
1
61
60
NC
AV
LOSLVS
SS
10
AV
DD
TXCLK4
TXPOS4
TXNEG4
TXCLK3
TXPOS3
TXNEG3
LOOPEN4
LOOPEN3
GND
TXCLK2
TXPOS2
TXNEG2
TXCLK1
TXPOS1
TXNEG1
LOOPEN2
LOOPEN1
E1/T1–
V
V
DD
SS
RXPOS3
RXNEG3
RXPOS4
RXNEG4
RXPOS2
RXNEG2
RXPOS1
RXNEG1
RV
DD
RV
SS
26
44
43
27
68 Lead PLCC
60
41
NC
NC
NC
NC
61
40
LPMOD1
TXEN2
TXEN1
TXOUT1
LPMOD2
RXIN1
LOS2
LOS1
RXIN2
TV
DD
TV
SS
TXOUT2
AGND
NC
TV
SS
RGND
RGND
RGND
NC
NC
TV
DD
AGND
NC
TXOUT3
RXIN3
LOS3
LOS4
RXIN4
LPMOD3
LPMOD4
TV
DD
SS
TV
TXOUT4
TXEN4
TXEN3
NC
80
21
1
20
80 Lead TQFP (14 x 14 x 1.4 mm)
Rev. 2.00
3
XR-T5793
PIN DESCRIPTION
PLCC
Pin #
SQFP
Pin #
Symbol
NC
Type
Description
1
2
3
4
71
72
73
74
No Connect.
TVDD
VDD
GND
O
Transmit VDD. )5V ($5%).
Analog Ground.
AGND
TXOUT3
Transmitter 3 Output. Transmitter 3 bipolar output connected to coupling
capacitor or pulse transformer by a resistor.
5
6
7
75
76
77
TVSS
TVDD
VSS
VDD
O
Transmit VSS. -5V ($5%).
Transmit VDD. +5V ($5%).
TXOUT4
Transmitter 4 Output. Transmitter 4 bipolar output connected to coupling
capacitor or pulse transformer by a resistor.
8
9
78
79
TXEN4
TXEN3
I
I
Transmitter 4 Output Enable. If driven high the transmitter 4 output drivers
are enabled. Hi-Z otherwise.
Transmitter 3 Output Enable. If driven high the transmitter 3 output drivers
are enabled. Hi-Z otherwise.
10
11
12
1, 2, 80
NC
NC
VDD
I
No Connect.
Analog VDD.
3,4
5
AVDD
TXCLK4
Transmitter 4 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
13
14
15
16
17
18
19
6
7
TXPOS4
TXNEG4
TXCLK3
I
I
I
I
I
I
I
Transmitter 4 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 4.
Transmitter 4 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 4.
8
Transmitter 3 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
9
TXPOS3
TXNEG3
LOOPEN4
LOOPEN3
Transmitter 3 Positive Data in. Positive data input in NRZ or RZ format for
transmitter 3.
10
11
12
Transmitter 3 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 3.
Loop Enable 4. If driven high the specified loop type will be enabled for
channel 4. Otherwise normal operation will continue.
Loop Enable 3. If driven high the specified loop type will be enabled for
channel 3. Otherwise normal operation will continue.
20
21
22
13
14
15
GND
VDD
GND
VDD
O
Digital Ground.
Digital VDD. +5V ($5%).
RXPOS3
Receiver 3 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 3.
23
24
25
26
16
17
RXNEG3
RXPOS4
RXNEG4
RVDD
O
O
Receiver 3 Positive Data Out. Negative data output in NRZ or RZ format for
receiver 3.
Receiver 4 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 4.
18
O
Receiver 4 Positive Data Out. Negative data output in NRZ or RZ format for
receiver 4.
19,20
VDD
Receive VDD. +5V ($5%).
Rev. 2.00
4
XR-T5793
PIN DESCRIPTION (CONT’D)
PLCC
Pin #
SQFP
Pin #
Symbol
Type
Description
27
28
29
21
22
23
LPMOD4
I
Loop Mode 4. If driven high the loopback mode of channel 4 will be set to re-
mote loop. Otherwise theloopback mode will remain at local loop. The
actualloopback will be activated when the LOOPEN4 is asserted.
LPMOD3
RXIN4
I
I
Loop Mode 3. If driven high the loopback mode of channel 3 will be set to re-
mote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN3 is asserted.
Receiver 4 Input. Receiver 4 bipolar input connected to coupling capacitor or
pulse transformer.
30
31
32
24
25
26
LOS4
LOS3
RXIN3
O
O
I
Receiver 4 Loss of Signal. Asserted during LOS condition. Clear otherwise.
Receiver 3 Loss of Signal. Asserted during LOS condition. Clear otherwise.
Receiver 3 Input. Receiver 3 bipolar input connected to coupling capacitor or
pulse transformer.
33
34
35
36
37
38
27
28
NC
NC
No Connect.
No Connect.
29, 30
31
RGND
RGND
NC
GND
GND
Receive Ground.
Receive Ground.
No Connect.
32
33
RXIN2
I
Receiver 2 Input. Receiver 2 bipolar input connected to coupling capacitor or
pulse transformer.
39
40
41
34
35
36
LOS1
LOS2
RXIN1
O
O
I
Receiver 1 Loss of Signal. Asserted during LOS condition. Clear otherwise.
Receiver 2 Loss of Signal. Asserted during LOS condition. Clear otherwise.
Receiver 1 Input. Receiver 1 bipolar input connected to coupling capacitor or
pulse transformer.
42
43
37
38
LPMOD2
LPMOD1
I
I
Loop Mode 2. If driven high the loopback mode of channel 2 will be set to re-
mote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN2 is asserted.
Loop Mode 1. If driven high the loopback mode of channel 1 will be set to re-
mote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN1 is asserted.
-
39, 40
41,42
43
NC
NC
VSS
O
No Connect.
44
45
RVSS
Receive VSS. -5V ($5%).
RXNEG1
Receiver 1 Negative Data Out. Negative data output in NRZ or RZ format for
receiver 1.
46
47
48
44
45
46
RXPOS1
RXNEG2
RXPOS2
O
O
O
Receiver 1 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 1.
Receiver 2 Negative Data Out. Negative data output in NRZ or RZ format for
receiver 2.
Receiver 2 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 2.
49
50
47
48
VSS
VSS
I
Digital VSS. -5V ($5%).
E1/T1-
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
Description
51
52
53
54
55
56
57
58
49
50
51
52
53
54
55
56
LOOPEN1
I
Loop Enable 1. If driven high the specified loopback mode will be enabled for
channel 1. Otherwise normal operation will continue.
LOOPEN2
TXNEG1
TXPOS1
TXCLK1
TXNEG2
TXPOS2
TXCLK2
I
I
I
I
I
I
I
Loop Enable 2. If driven high the specified loopback mode will be enabled for
channel 2. Otherwise normal operation will continue.
Transmitter 1 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 1.
Transmitter 1 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 1.
Transmitter 1 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
Transmitter 2 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 2.
Transmitter 2 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 2.
Transmitter 2 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.
59
60
57,58,59
60
AVSS
VSS
I
Analog VSS.
LOSLVS
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
63
NC
NC
I
No Charge.
61
TXEN2
Transmitter 2 Output Enable. If asserted the transmitter 2 output drivers are
enabled. High-Z otherwise.
62
63
64
65
TXEN1
I
Transmitter 1 Output Enable. If asserted the transmitter 1 output drivers are
enabled. High-Z otherwise.
TXOUT1
O
Transmitter 1 Output. Transmitter 1 bipolar output connected to coupling
capacitor or pulse transformer through a resistor.
64
65
66
66
67
68
TVDD
TVSS
VDD
VSS
O
Transmit VDD. +5V ($5%).
Transmit VSS. -5V ($5%).
TXOUT2
Transmitter 2 Output. Transmitter 2 bipolar output connected to coupling
capacitor or pulse transformer through a resistor.
67
68
69
70
AGND
TVSS
GND
VSS
Analog Ground.
Transmit VSS. –5V ($5%).
Rev. 2.00
6
XR-T5793
DC ELECTRICAL CHARACTERISTICS
Test Conditions: T = -40°C to 25°C to 85°C, all V s = 5V $5%, all V s = -5V $5%, all GNDs = 0V
A
DD
SS
Symbol
Parameter
Min.
Typ.
Max.
Unit
Conditions
DC Parameters
VDD
s
DC Supply Positive
DC Supply Negative
4.75
5.00
5.25
V
V
VSS
s
-4.75
-5.00
-5.25
Inputs
VIH
VIL
High Level Input
2.0
V
V
Low Level Input
0.8
40
IPDC
Input Pull Down Current
µA
Outputs
VOH
High Level Output
High Level Output
Low Level Output
3.5
V
V
V
IOH = -10µA
IOH = -40µA
IOL = 1.6mA
VOH
2.4
VOL
0.4
Receiver Specifications
RXP
Receiver Sensitivity
0.6
0
4.2
12
12
Vp
dB
dB
dB
%
RXCL
Allowed Cable Loss
10
10
1.024MHz (E1)
772kHz (T1)
(0dB=2.4V)
0
RXIWT
RXTI
Interference Margin (E1)
Receiver Slicing Level (T1)1
Receiver Slicing Level (E1)1
Receiver LOS Threshold
Input Resistance
16
60
45
with 6dB cable loss
Peak Voltage %
Peak Voltage %
65
50
70
55
RXEI
%
RXLOS
RIN
0.2
0.3
V
2.5
kΩ
Up to 3.072MHz
Power Specifications (Without Monitor Channel)
PD
PD
Power Dissipation
400
250
500
475
450
680
280
833
860
830
mW
mW
mW
mW
mW
mW
Power Dissipation
All Drivers in High-Z
PC
Power Consumption 75Ω2
Power Consumption 100Ω2
Power Consumption 120Ω2
Power Supply Requirement
All 1’s Transmit & Receive
All 1’s Transmit & Receive
All 1’s Transmit & Receive
PC
PC
PVDD
Pc/2
+5mW
Pvss
Power Supply Requirement
Pc/2
- 5mW
mW
Notes
1
2
Selected by E1/T1-
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: T = -40°C to 25°C to 85°C, all V s = 5V $5%, all V s = -5V $ 5%, all GNDs = 0V
A
DD
SS
Symbol
Parameter
Min.
Typ.
Max.
Unit
Conditions
AC PARAMETERS
VTXOUT
VTXOUT
VTXOUT
Output Pulse Amplitude
(75Ω)
2.13
2.70
2.3
2.37
3.0
2.60
3.30
3.7
V
V
V
Output Pulse Amplitude
(120Ω)
Output Pulse Amplitude
(100Ω)
3.0
TXPW
TXPW
Pulse Width (2.048MHz)
Pulse Width (1.544MHz)
Pos/neg Pulse Imbalance
TXCLK Clock Period (E1)
TXCLK Clock Period (T1)
TXCLK Duty Cycle
224
274
-5
244
324
264
374
+5
ns
ns
%
Determined by TX Clock
Determined by TX Clock
T1
T2
T3
T4
488
648
50
ns
ns
%
48
52
Data Setup Time, TDATA to
TCLK
50
ns
T5
TR
TF
T6
T7
Data Hold Time, TCLK to TDATA
Clock Rise Time
50
ns
ns
ns
ns
ns
30
30
Clock Fall Time
Receive Data High (E1)
Data Propagation Delay
219
244
269
0dB Cable Loss
T1
T2
) 100
) 100
T1
T2
T8
Data Propagation Delay
ns
Specifications are subject to change without notice
ABSOLUTE MAXIMUM RATINGS
Storage Temperature . . . . . . . . . . . . -65°C to +150°C
Operating Temperature . . . . . . . . . . . . -40°C to +85°C
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $7V
Rev. 2.00
8
XR-T5793
T or T
1
F
T
3
T
3
T
R
T
F
TXCLK(n)
T
4
T
5
TXPOS(n)
TXNEG(n)
Figure 2. Transmit Timing Diagram
T
7
T
6
T
R
T
F
RXIN
T
8
RXPOS
RXNEG
T
F
T
R
T
6
Figure 3. Receive Timing Diagram
Rev. 2.00
9
XR-T5793
Transmit Interface
75Ω
75Ω
100Ω
100Ω
120Ω
120Ω
Min.
18
Typ.
22
Min.
18
Typ.
22
Min.
18
Typ.
22
Units
dB
51kHz to 102kHz
102kHz to 2.048MHz
2.048MHz to 3.072MHz
18
22
18
22
18
22
dB
18
22
18
22
18
22
dB
Receive Interface
Min.
20
Typ.
30
Min.
20
Typ.
30
Min.
20
Typ.
30
Units
dB
51kHz to 102kHz
102kHz to 2.048MHz
2.048MHz to 3.072MHz
20
30
20
30
20
30
dB
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
75Ω
RLOAD
75Ω
Turns Ratio
1:1
Line Impedance
75Ω
ROUT
68Ω
68Ω
62Ω
1:1
1:1
1:1
120Ω
120Ω
100Ω
1:1.265
1:1.265
120Ω
100Ω
100Ω
Table 2. Input Transformer Requirements
Magnetic Supplier Information:
Table 3. Output Transformer Requirements
Pulse
Transpower Technologies, Inc.
24 Highway 28, Suite 202
Crystal Bay, NV 89402–0187
Tel. (702) 831–0140
Telecom Product Group
P.O. Box 12235
San Diego, CA 92112
Tel. (619) 674-8100
Fax. (619) 674-8262
Fax. (702) 831–3521
Rev. 2.00
10
XR-T5793
SYSTEM DESCRIPTION
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.
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 TTLcompatible
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
Transmissionispossibleeitherwithorwithoutaclock. Ifa
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.
inputs.
More than one channel can be tested
simultaneously.
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
TXOUT
RX
TX
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
TXOUT
RX
TX
LPMOD=0
LPEN=1
A balanced signal (100Ω or 120Ω) must be coupled by a
transformer. Anunbalancedsignal(75Ω)maybecoupled
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
XR-T5793
Output Transformer Selection
3. Calculate the source resistance, Rs.
VS
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:
ǒ Ǔ
* 1
RS + Req
Veq
4. Now calculate the theoretical return loss.
Req ) RS
Return Loss + 20 log ǒ Ǔ
Req * RS
D Driver output impedance is less than 5Ω.
D 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.
Transformer Ratio = 1:1.265
1. List the application requirements.
Transformer ratio = 1:n
V = 3.0V Peak
O
R = 120Ω
L
V = Peak output pulse amplitude
O
R = Load resistance
L
RL
n2
120
1.6
Req +
Veq +
+
+
+ 75Ω
Rs
1:n
Vo
n
3.0
1.265
1
2
3
4
+ 2.37V
V
O
Vs
R
L
VS
ǒ 4.5 Ǔ + 67.4Ω
Rs + Req ǒ Ǔ+ 75
* 1
* 1
2.37
Veq
Figure 5. Equivalent Impedance Schematic
2. Calculate equivalent output voltage and load
resistance without the transformer.
(Datasheet specifies standard value of 68Ω)
Calculate the theoretical return loss to determine if the
transformer is acceptable.
RL
+
VO
+
Req
Veq
n2
n
ǒ75 ) 67.4Ǔ + 25.5dB
Return Loss + 20 log
Rs
75 * 67.4
V
eq
Vs
Req
Figure 6. Equivalent Simplified Schematic
Rev. 2.00
12
XR-T5793
269 ns
(244 + 25)
Nominal pulse
20%
20%
10%
10%
V = 100%
194 ns
(244 – 50)
50%
244 ns
219 ns
(244 – 25)
10%
10%
10%
10%
0%
20%
488 ns
(244 + 244)
Note: V corresponds to the nominal peak value
Figure 7. CCITT G.703 Pulse Template
Rev. 2.00
13
XR-T5793
68 LEAD PLASTIC LEADED CHIP CARRIER
(PLCC)
Rev. 1.00
D
C
Seating Plane
D
45° x H1
1
A
2
45° x H2
2 1 68
B
1
B
D
D
2
3
D
D
1
e
R
D
3
A
1
A
INCHES
MILLIMETERS
SYMBOL
MIN
MAX
MIN
MAX
A
A
A
B
B
0.165
0.090
0.020
0.013
0.026
0.008
0.985
0.950
0.890
0.200
0.130
---.
4.19
2.29
5.08
3.30
---
1
2
0.51
0.021
0.032
0.013
0.995
0.958
0.930
0.33
0.53
0.81
0.32
25.27
24.33
23.62
0.66
1
C
D
D
D
D
e
0.19
25.02
24.13
22.61
1
2
3
0.800 typ.
0.050 BSC
20.32 typ.
1.27 BSC
H1
H2
R
0.042
0.056
0.048
0.045
1.07
1.42
1.22
1.14
0.042
0.025
1.07
0.64
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
D
1
60
41
61
40
D
D
1
80
21
1
20
A
B
2
e
C
A
α
Seating Plane
A
1
L
INCHES
MILLIMETERS
SYMBOL
MIN
MAX
MIN
MAX
A
0.055
0.002
0.053
0.009
0.004
0.622
0.547
0.063
0.006
0.057
0.015
0.008
0.638
0.555
1.40
0.05
1.60
0.15
A
1
A
2
B
1.35
1.45
0.22
0.38
C
D
D
e
0.09
0.20
15.80
13.90
16.20
14.10
0.65 BSC
0.75
1
0.0256 BSC
L
0.018
0.030
0.45
α
0°
7°
0°
7°
Note: The control dimension is the millimeter column
Rev. 2.00
15
XR-T5793
NOTICE
EXAR Corporation reserves the right to make changes to the products contained in this publication in order to im-
prove design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits de-
scribed 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 circum-
stances.
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
相关型号：
XRT5997IV-F
PCM Transceiver, 1-Func, CEPT PCM-30/E-1, CMOS, PQFP100, 14 X 14 MM, 1.40 MM HEIGHT, GREEN, TQFP-100
EXAR
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