ETC TXC-02050-AIPL

MRT
Two Terminal Side interfaces are provided, a positive and negative rail (RP and RN) or NRZ (RD) interface.
The selection is determined by the state placed on the signal lead labeled PNENB. When a low is applied to
the signal lead, the HDB3 Decoder and HDB3 Encoder Blocks are bypassed, and the terminal side I/O is a
positive and negative rail interface. When a high is applied to the signal lead, an NRZ interface is provided.
Data is clocked out of the MRT on negative edges of the clock signal (CLKO). Receive data and the clock signals are disabled, and forced to a high impedance state by placing a low on the receive disable lead (RXDIS).
For a receive positive and negative rail interface, an inverted clock (CLKO) is also provided.
The terminal side interface for the transmitter can either be positive and negative rail (TP and TN) or NRZ (TD)
data depending on the state of the common control lead PNENB. Data is clocked into the MRT on positive
transitions of the clock signal (CLKI). The input clock is monitored for the loss of clock. When the input clock
remains high or low, TXLOC will be set low. The MRT also provides the capability to generate and insert AIS
(all ones signal), independent of the transmit data. A low placed on the TXAIS lead enables the transmit AIS
generator.
Two loopbacks are provided, transmit loopback and receive loopback. Transmit loopback connects the data
path from the transmitter output driver stage to the clock recovery, and disables the external receiver input.
Transmit loopback is activated by placing a low on the LBKTX signal lead.
Receive loopback connects the receive data path to the transmit output circuits and disables the transmit input.
Receive loopback is activated by placing a low on the LBKRX signal lead.
For 6 Mbps operation, the MRT should be operated in the P and N rail mode, bypassing the HDB3 Decoder/
Encoder.
TP/TD
40
TN
VDD
TXAIS
42
44
GND
8
38
CLKI
10
36
VCOC
PNENB
GND
GND
TXLOC
2
RXAIS
BERCK
4
GND
6
LQLTY
PIN DIAGRAM
VDD
DCK
VDD
RN
MRT PIN DIAGRAM
(Top View)
12
RP/RD
CLKO
34
32
14
GND
GNDA
30
DI2
28
DI1
EQB0
EQB1
26
LOW
LBKTX
24
LBKRX
VAGC
22
AGFIL
20
RXDIS
RXLOS
CV
18
16
VDD
PLLC
TPO
TNO
CLKO
GND
GND
VDD
GND
Figure 2. MRT Pin Diagram With Names and Numbers
-3-
TXC-02050-MB
Ed. 3, April 1994
MRT
PIN DESCRIPTIONS
Power Supply and Ground
Symbol
Pin No.
I/O/P*
Type
Name/Function
VDD
10,18,35,
37,42
P
VDD: 5-volt supply, ± 5%.
GND
1,6,11,16,32,
36,39,44
P
Ground: 0 volts reference.
VAGC
23
P
AGC VDD: Isolate from VDD using 1N914 or 1N4148
diode.
GNDA
31
P
AGC Ground: 0 volts reference.
*Note: I = Input; O = Output; P = Power
Line Side I/O
Symbol
Pin No.
I/O/P
Type
Name/Function
DI1
29
I
Analog
Data In 1: HDB3 or B8ZS encoded bipolar receive
data input.
DI2
30
O
Analog
Data In 2: DC Voltage Reference for Data Input DI1.
The MRT uses an internally generated voltage reference as an AC ground for the received data input. An
external 0.1 µF capacitor, in parallel with a 10 µF/6.3 V
tantalum capacitor, is connected between this pin and
ground. No other connection should be made to this
pin.
TNO
33
O
TTL24mA
Transmit Negative Out: Line transmit negative; output is an active low.
TPO
34
O
TTL24mA
Transmit Positive Out: Line transmit positive; output
is an active low.
Symbol
Pin No.
I/O/P
Type
Name/Function
RN
12
O
TTL4mA
Receive Negative: When PNENB is low, the HDB3
codec is bypassed and N-rail (RN) data is provided on
this pin. When PNENB is high, the output is forced to
a high impedance state.
RP/RD
13
O
TTL4mA
Receive Positive/Receive Data: When PNENB is
low, the HDB3 codec is bypassed and P-Rail (RP)
data is provided on this pin. When PNENB is high,
NRZ data (RD) is provided.
CLKO
14
O
CMOS8mA
Terminal Side I/O
Clock Out Inverted: Receive inverted clock output.
Positive and negative rail receive data is clocked out
on the rising edge. Disabled in the NRZ mode.
-4-
TXC-02050-MB
Ed. 3, April 1994
MRT
Symbol
Pin No.
I/O/P
Type
Name/Function
CLKO
15
O
CMOS8mA
Clock Out: Receive clock output. Receive positive
and negative rail and NRZ data is clocked out on the
falling edge.
CLKI
38
I
TTLr
Clock In: Transmit clock input for P and N rail and
NRZ data. Transmit data is clocked into the MRT on
the rising edge. This clock must have a frequency of
± 20 ppm for the 34368 kbit/s operation and ± 30 ppm
for the 6312/8448 kbit/s operation (ref: CCITT recommendation G.703). The duty cycle requirement for this
clock signal is 50% ± 5%, measured at the 1.4V TTL
threshold level.
TP/TD
40
I
TTL
Transmit Positive/Transmit Data: When PNENB is
low, the HDB3 codec is bypassed and transmit P-rail
(TP) data is applied to this pin. When PNENB is high,
NRZ transmit data (TD) is applied.
TN
41
I
TTL
Transmit Negative: When PNENB is low, the HDB3
codec is bypassed and transmit N-Rail (TN) is applied
to this pin. When PNENB is high, this input is disabled.
Alarm Signal Outputs
Symbol
Pin No.
I/O/P
Type
Name/Function
TXLOC
2
O
TTL2mA
Transmit Loss Of Clock: Active low output. A transmit loss of clock alarm occurs when the transmit clock
input (CKLI) is stuck high or low for 20-32 clock cycles.
Recovery occurs on the first input clock transition.
LQLTY
5
O
TTL2mA
Line Quality: This signal represents a gross estimate
of the line quality which is determined by counting
coding violations for 34 (8) Mbit/s operation. If the line
error rate exceeds a 10-6 threshold during a 10 (40)
second interval, LQLTY goes active high. LQLTY is
active low when coding violations do not exceed the
10-6 threshold in a 10 (40) second interval. The output
on this pin is only valid when the appropriate clock signal is applied to BERCK. It should be disregarded in
the P and N mode of operation.
CV
19
O
TTL2mA
Coding Violation: Active high output. A coding violation pulse occurs when an HDB3 coding violation is
detected in the received line data input. A coding violation is not part of the HDB3 zero-substitution code. A
coding violation occurs because of noise or other
impairments affecting the line signal. The output of this
pin should be disregarded in the P and N mode.
RXLOS
20
O
TTL2mA
Receive Loss Of Signal: Active low output. A receive
loss of signal occurs when the input data is zero for
20-32 clock cycles. Recovery occurs when the receive
signal returns.
-5-
TXC-02050-MB
Ed. 3, April 1994
MRT
MRT Control Leads
Symbol
Pin No.
I/O/P
Type
Name/Function
RXAIS
3
I
CMOSr
Receive Alarm Indication Signal: When RXAIS is
low, the MRT generates AIS (all ones signal) for the
terminal side receive output data. The line side
receive data path is disabled. The reference clock
(DCK) provides the clock source required for generating AIS.
BERCK
4
I
TTLr
Bit Error Rate Clock: This clock establishes the time
base for estimating the coding violation error rate. For
34 Mbit/s operation the clock frequency must be 6
kHz, and for 8 Mbit/s operation the clock frequency
must be 1.5 kHz. This pin should be left open for P
and N mode operation.
PNENB
8
I
CMOSr
P And N Enable: When PNENB is low, the P and N
rail interface is enabled, and the HDB3 codec is
bypassed. When PNENB is high, the terminal side I/O
data is NRZ and the HDB3 codec is enabled. This pin
must be held low for 6 Mbit/s operation.
DCK
9
I
TTL
Reference Clock: Operating frequency reference
clock. For receive signal clock recovery, ± 200 ppm
frequency accuracy is adequate. If the transmit and
receive AIS features are used, the frequency accuracy
must be ± 20 ppm for 34368 kbit/s and ± 30 ppm for
8448 and 6312 kbit/s operation. The duty cycle
requirement for this clock signal is 50% ± 5% as measured at the 1.4V TTL threshold level.
RXDIS
21
I
CMOSr
Receive Disable: When RXDIS is low, the receive
side of the MRT is disabled and the RN, RP/RD,
CLKO and CLKO output leads are forced to a high
impedance state.
LBKRX
24
I
CMOSr
Loopback Receive: When LBKRX is low, the MRT
loops back receive data as transmit data. The receive
data is also sent to the terminal side, but the transmit
data input on the terminal side is disabled. (Note 1)
LBKTX
25
I
CMOSr
Loopback Transmit: When LBKTX is low, the MRT
loops back transmit data as receive data. The transmit
data is sent on the line side, but the receive data input
on the line side is disabled. (Note 1)
LOW
26
I
CMOSr
Low Frequency: When LOW is low, the MRT enables
equalization and input attenuator settings for 6312 or
8448 kbit/s operation. This lead also controls the clock
recovery high/low frequency range circuit.
Note 1: Setting LBKTX and LBKRX low simultaneously will cause invalid outputs at the receive terminal and transmit line
ports.
-6-
TXC-02050-MB
Ed. 3, April 1994
MRT
Symbol
Pin No.
I/O/P
Type
Name/Function
EQB1
EQB0
27
28
I
I
CMOSr
Equalizer Bit 1: MSB of equalizer setting.
Equalizer Bit 0: LSB of equalizer setting. Equalization
is as follows for 34 Mbit/s operation:
EQB1 EQB0 CABLE EQUALIZATION √f *
1
1
0dB< cable <3.5dB
1
0
2.6dB<cable<8dB
0
0
6dB<cable<9.9dB
0
1
8.6dB<cable<13.2dB
For 8 or 6 Mbit/s operation:
1
1
0dB< cable< 4.1dB
1
0
2.5dB<cable<6.5dB
* f = 1/2 the bit rate
TXAIS
43
I
CMOSr
Transmit AIS: When TXAIS is low, the MRT sends an
AIS (all ones signal) for the line side transmit output
data. The terminal side transmit data path is disabled.
The reference clock (DCK) provides the clock required
for generating AIS.
Pins With External Components
Symbol
Pin No.
I/O/P
Type
Name/Function
VCOC
7
I/O
Analog
Voltage Controlled Oscillator Capacitor: For 6, 8,
and 34 Mbit/s operation, a 470Ω ± 5%, 1/8 watt resistor is connected in series with a 0.1 µF ± 10% capacitor to ground. These components are used in the
phase-locked loop filter.
PLLC
17
I/O
Analog
Phase-Locked Loop Capacitor: 0.1 µF ± 10%
ceramic disk capacitor connected to ground.
AGFIL
22
I/O
Analog
Automatic Gain Filter: For 6/8 MHz mode, 0.01 µF ±
10% ceramic disk capacitor connected to ground. For
34 Mbit/s mode, open.
-7-
TXC-02050-MB
Ed. 3, April 1994
MRT
ABSOLUTE MAXIMUM RATINGS*
Parameter
Symbol
Min
Max
Unit
Supply voltage
VDD
-0.3
7.0
V
AGC Supply Voltage
VAGC
-0.5
6.5
V
DC input voltage
VIN
-0.5
VDD + 0.5
V
Continuous power dissipation
PC
750
mW
Ambient operating temperature
TA
85
oC
Operating junction temperature
TJ
150
oC
Storage temperature range
TS
150
oC
-40
-55
*Note: Operating conditions exceeding those listed in Absolute Maximum Ratings may cause permanent failure. Exposure
to absolute maximum ratings for extended periods may impair device reliability.
THERMAL CHARACTERISTICS
Parameter
Min
Typ
Thermal Resistance:
Junction to Ambient
Max
Unit
46
oC/W
Test Conditions
POWER REQUIREMENTS
Parameter
Min
Typ
Max
Unit
VDD
4.75
5.0
5.25
V
VAGC
VDD - 0.7
VDD - 0.5
V
IDD
100
mA
VDD = 5.25V
IAGC
20
mA
VAGC = 4.75V
PDD
525
mW
VDD = 5.25V
PAGC
95
mW
VAGC = 4.75V
-8-
Test Conditions
Isolated from VDD via a
IN4148 or 1N914 diode.
TXC-02050-MB
Ed. 3, April 1994
MRT
INPUT, OUTPUT, AND I/O PARAMETERS
Input Parameters For TTL
Parameter
Min
VIH
Typ
Max
2.0
Unit
Test Conditions
V
4.75 <VDD < 5.25
VIL
0.8
V
4.75 <VDD < 5.25
Input leakage current
10
µA
VDD = 5.25
Input capacitance
5.5
pF
Input Parameters For TTLr
Parameter
Min
Typ
Max
2.0
VIH
VIL
Input leakage current
50
Input capacitance
5.5
Unit
Test Conditions
V
4.75 <VDD < 5.25
0.8
V
4.75 <VDD < 5.25
120
µA
VDD = 5.25
pF
Note: Input has a 100K (nominal) internal pull-up resistor.
Input Parameters For CMOSr
Parameter
VIH
Min
Typ
Max
2.0
VIL
Input leakage current
50
Input capacitance
5.5
Unit
Test Conditions
V
4.75 <VDD < 5.25
0.8
V
4.75 <VDD < 5.25
120
µA
VDD = 5.25
pF
Note: Input has a 100K (nominal) internal pull-up resistor.
Output Parameters For TTL2mA
Parameter
VOH
Min
Typ
Max
VDD - 0.5
Unit
Test Conditions
V
VDD = 4.75; IOH = -1.0 mA
VDD = 4.75; IOL = 2.0 mA
VOL
0.4
V
IOL
2.0
mA
IOH
-1.0
mA
tRISE
5.5
12.5
18.2
ns
CLOAD = 15pF
tFALL
2.3
4.4
6.5
ns
CLOAD = 15pF
-9-
TXC-02050-MB
Ed. 3, April 1994
MRT
Output Parameters For TTL4mA
Parameter
VOH
Min
Typ
Max
VDD - 0.5
Unit
Test Conditions
V
VDD = 4.75; IOH = -2.0 mA
VDD = 4.75; IOL = 4.0 mA
VOL
0.4
V
IOL
4.0
mA
IOH
-2.0
mA
tRISE
2.8
6.5
9.2
ns
CLOAD = 15 pF
tFALL
1.3
2.3
3.4
ns
CLOAD = 15 pF
Typ
Max
Unit
Output Parameters For TTL24mA
Parameter
Min
VDD - 0.5
VOH
Test Conditions
V
VDD = 4.75; IOH = -12.0 mA
VDD = 4.75; IOL = 24.0 mA
VOL
0.4
V
IOL
24.0
mA
IOH
-12.0
mA
tRISE
0.8
1.4
1.8
ns
CLOAD = 25 pF
tFALL
0.5
0.8
1.0
ns
CLOAD = 25 pF
Typ
Max
Unit
Output Parameters For CMOS8mA
Parameter
VOH
Min
VDD - 0.5
Test Conditions
V
VDD = 4.75; IOH = -8.0 mA
VDD = 4.75; IOL = 8.0 mA
VOL
0.4
V
IOL
8.0
mA
IOH
-8.0
mA
tRISE
1.3
2.4
3.8
ns
CLOAD = 25 pF
tFALL
1.1
1.8
2.5
ns
CLOAD = 25 pF
- 10 -
TXC-02050-MB
Ed. 3, April 1994
MRT
TIMING CHARACTERISTICS
Detailed timing diagrams for the MRT are illustrated in Figures 3 through 9. All output times are measured with
maximum load capacitance appropriate for the pin type. Timing parameters are measured at (VOH - VOL)/2 or
(VIH - VIL)/2 as applicable.
Line Side Timing Characteristics
The line side timing characteristics of the MRT are designed so that the line output mask at the transformer
output meets the wave shapes specified in CCITT recommendation G.703 for 34 and 8 Mbit/s operation and
the NTT Technical Reference for High Speed Digital Leased Circuit Service for 6 Mbit/s operation. The pulse
masks for each of the three modes of operation are shown in Figures 3, 4, and 5. Refer to the corresponding
standard cited in each case for further details regarding the interface.
Figure 3. Pulse Mask at the 34368 kbit/s Interface
17 ns
(14.55 + 2.45)
0.1
0.2
V
1.0
0.2
0.1
8.65 ns
(14.55 - 5.90)
Nominal pulse
14.55 ns
0.5
12.1 ns
(14.55 - 2.45)
0.1
0.1
0
0.1 0.1
24.5 ns
(14.55 + 9.95)
29.1 ns
(14.55 + 14.55)
Reference: CCITT Recommendation G.703
- 11 -
TXC-02050-MB
Ed. 3, April 1994
MRT
Figure 4. Pulse Mask at the 8448 kbit/s Interface
69 ns
(59 + 10)
0.474
0.237
V
35 ns
0.474
0.237
2.370
(59 - 24)
Nominal pulse
59 ns
1.185
49 ns
(59 - 10)
0.237 0.237
0.237 0.237
0
100 ns
(59 + 41)
118 ns
(59 + 59)
Reference: CCITT Recommendation G.703
Figure 5. Pulse Mask at the 6312 kbit/s Interface
Horizontal axis 20 ns/div
Vertical axis
1 V/div
Pulse amplitude
B
A
(0,2)
F
Nominal
pulse
shape
G
(0,1)
H
I
Coordinates of each point
A : ( 0, 2.3) F : ( 0, 1.7)
B : (2.4, 2.3) G : (0.4, 1.7)
C : (2.4, 1.0) H : (1.6, 0.9)
D : (3.2, 0.3) I : (1.6, 0.3)
E : (4.0, 0.3)
(0,0)
C
D
E
(4,0)
Time
Reference: NTT Technical Reference for
High-Speed Digital Leased Circuit Services
- 12 -
TXC-02050-MB
Ed. 3, April 1994
MRT
Terminal Side Timing Characteristics
Figure 6. NRZ Transmit Input
tPWH
tCYC
CLKI
1.4V
tSU
TP,TD
DATA
VALID
tH
DATA
VALID
Parameter
Symbol
CLKI clock period
DATA
VALID
Min
tCYC
Typ
Max
Unit
Note 2
ns
CLKI duty cycle (tPWH/tCYC)
--
45
55
%
TP,TD set-up time to CLKI↑
tSU
3
ns
TP,TD hold time after CLKI↑
tH
2
ns
Note 1: CLKI symmetry is measured about the 1.4VDC threshold in order to assure symmetric output waveforms.
Note 2: The clock input can be 6, 8, or 34 MHz (refer to page 5).
Figure 7. NRZ Receive Output
tPWH
tCYC
CLKO
tOD(1)
RP,RD
tOD(2)
CV
Parameter
CLKO clock period
CLKO duty cycle (tPWH/tCYC)
Symbol
Min
tCYC
Typ
Max
Note 2
Unit
ns
--
45
55
%
RP,RD output delay after CLKO↓
tOD(1)
-5
5
ns
CV output delay after CLKO↓
tOD(2)
-5
5
ns
Note 1: CKLO symmetry is measured about the 50% amplitude point.
Note 2: The clock output can be 6, 8, or 34 MHz (refer to page 4).
- 13 -
TXC-02050-MB
Ed. 3, April 1994
MRT
Figure 8. P and N Rail Transmit Input
tPWH
tCYC
CLKI
1.4V
tSU
tH
TP,TD
DATA
VALID
DATA
VALID
DATA
VALID
TN
DATA
VALID
DATA
VALID
DATA
VALID
Parameter
Symbol
CLKI clock period
Min
Typ
tCYC
CLKI duty cycle (tPWH/tCYC)
Max
Note 2
Unit
ns
--
45
55
%
TP,TD & TN set-up time to CLKI↑
tSU
3
ns
TP,TD & TN hold time after CLKI↑
tH
2
ns
Note 1: CLKI symmetry is measured about the 1.4VDC threshold.
Note 2: The clock input can be 6, 8, or 34 MHz (refer to page 5).
tOD(1)
Figure 9. P and N Rail Receive Timing
tCYC
tPWH
CLKO
CLKO
RP,RD
tOD(2)
RN
Parameter
CLKO clock period
CLKO duty cycle (tPWH/tCYC)
Symbol
Min
tCYC
--
CLKO output delay after CLKO↑
tOD(1)
RP, RD and RN output delay after CLKO↓
tOD(2)
Typ
Max
Note 2
45
-5
Unit
ns
55
%
2
ns
6
ns
Note 1: CLKO symmetry is measured about the 50% amplitude point.
Note 2: The clock output can be 6, 8, or 34 MHz (refer to page 4).
- 14 -
TXC-02050-MB
Ed. 3, April 1994
MRT
OPERATION
POWER SUPPLY
IN914 or IN4148
10/6.3v
Ferrite Bead
Fair Rite 2743002111
23
VAGC
A
VDD
VDD
31
GNDA
VDD
A
VDD
A
10
10/6.3v
18
D
35
D
37
+5V
A
+
D
D
D
42
D
VDD
GND
GND
GND
GND
GND
GND
GND
GND
+
1
6
11
16
32
36
39
44
D
All capacitors are
0.1 microfarad
unless otherwise
specified
D
TXC-02050
Figure 10. MRT Power Supply Connections
The MRT device has separate power supply pins labeled VDD and VAGC. The VAGC supply pin is connected
to the internal AGC amplifier and requires isolation from the VDD supply as indicated in Figure 10. Separate
bypass networks must be used for connecting the VDD and VAGC supply pins on the MRT to +5V. The bypass
network on the VAGC pin consists of an IN4148 or IN914 diode, and a 10/6.3 volt microfarad (tantalum) capacitor connected in parallel with a 0.1 microfarad capacitor, as shown in Figure 10. TranSwitch recommends that
the 0.1 microfarad decoupling capacitors be of RF quality and that they be connected in close proximity to the
device.
- 15 -
TXC-02050-MB
Ed. 3, April 1994
MRT
OVERVIEW
Line Side Input Impedance
The input impedance of the MRT is a function of the state of the LOW lead and the operating rate. Table 1 lists
the input impedance of the MRT at the operating line rates (which are 1/2 the bit rates).
Table 1. MRT Input Impedance
Condition
Minimum Input Impedance, | Z |
LOW = 1, line rate = 17184 kbit/s
1260 ohms
LOW = 0, line rate = 4224 kbit/s
2390 ohms
LOW = 0, line rate = 3156 kbit/s
3670 ohms
Line Side Input Sensitivity
The input voltage sensitivity of the MRT depends on the state of the LOW lead as shown in Table 2 below.
Table 2. MRT Input Sensitivity
Input Sensitivity (peak volts)
Min
Max
LOW Lead
0
0.5
2.7
(6 & 8 Mbit/s)
1
0.15
1.1
(34 Mbit/s)
Line Side Input Circuit
The circuit shown in Figure 11 illustrates the component required for operating the MRT device for 34368,
8448 or 6312 kbit/s. The transformer should have a frequency response of 0.2 to 80 MHz with an insertion loss
of 1 dB, maximum. TranSwitch recommends the use of a Coilcraft transformer (part no. WB-1010) or equivalent). This gives return loss and isolation voltage values that meet or exceed requirements.
1:1
29
Receive
Data
Input
75
5%
+
10/6.3
30
+
0.1
10/6.3
TXC-02050
MRT
Device
0.1
Figure 11. Line Side Input Circuit
Line Side Output Characteristics
The line side output of the MRT switches from “rail to rail” on both of its output leads, TPO and TNO. This provides the maximum voltage swing, and makes the output voltage depend on the +5 volt power supply input to
the chip. The external circuit design must therefore be done with care in order to assure the meeting of the
amplitude requirements.
- 16 -
TXC-02050-MB
Ed. 3, April 1994
MRT
Line Side Output Circuits
Figure 12 illustrates the output circuit required for operating the MRT device for a 34368 kbit/s application. The
transformer and resistors shown assure that the output waveform meets the CCITT mask for 34368 kbit/s
transmission and that the MRT device is operated within the current limits of the TTL24mA output parameters
on page 10. The transformer should have a frequency response of 0.1 - 100 MHz with an insertion loss of 1dB,
maximum.
1:2
150
Transmit
Data
Output
34
33
TXC-02050
MRT
Device
150
Figure 12. Line Side Output Circuit Outline (34368 kbit/s)
Figure 13 shows a variation of the circuit in Figure 12. This circuit improves performance in applications when
a plastic device is mounted in a socket. The additional low-pass filter compensates for possible overshoot
caused by inductance created by the device/socket interface. The transformer should have a frequency
response of 0.1 - 100 MHz with an insertion loss of 1dB, maximum.
1:2
75
100
Transmit
Data
Output
34
18 pf
100
33
TXC-02050
MRT
Device
75
18 pf
Figure 13. Line Side Output Circuit Outline (34368 kbit/s)
The peak voltage and current output requirements for 6312 and 8448 kbit/s operation are different from that
required for 34368 kbit/s operation. The output circuit in Figure 14 illustrates the output circuit required for
6312 kbit/s and 8448 kbit/s operation. The transformer should have a frequency response of .01 - 50 MHz with
an insertion loss of 1dB, maximum. The transformer, drivers and resistors assure that the output waveform
meets the CCITT masks for these rates and that the MRT device is operated within the current limits of the
TTL24mA output parameters on page 10.
1:1
R1
Transmit
Data
Output
34
33
TXC-02050
MRT
Device
R2
ACT11034
For 8448 kbit/s operation: R1 and R2 = 27Ω
For 6312 kbit/s operation: R1 and R2 = 36Ω
Figure 14. Line Side Output Circuit Outline (8448 and 6312 kbit/s)
- 17 -
TXC-02050-MB
Ed. 3, April 1994
MRT
Jitter Tolerance
CCITT Recommendation G.823 specifies that network equipment must be able to accommodate and tolerate
levels of jitter up to certain specified limits. The MRT accommodates and tolerates more input jitter than the
level of input jitter specified by the CCITT.
With input jitter applied to the MRT line side receive input DI1 (pin 29), the MRT properly recovers clock,
decodes the HDB3, and outputs error-free NRZ data over (and beyond) the CCITT specified jitter input and
frequency ranges. Performance characteristics are shown below in Figure 15 (34.368 Mbit/s operation) and
Figure 16 (8.448 Mbit/s operation).
LOG SCALE
Measured
10.0
30
kHz
INPUT JITTER
UI (PEAK- PEAK)
Minimum Requirement
Acceptance
Range
1.0
CCITT Rec. G.823 Limit
0.1
10Hz
100Hz
10kHz
1kHz
Frequency
100kHz
1MHz
LOG SCALE
Figure 15. MRT Jitter Tolerance at34.368 Mbit/s
(VDD = 5V, TA = 25oC)
LOG SCALE
Measured
10.0
10
kHz
INPUT JITTER
UI (PEAK- PEAK)
Minimum Requirement
1.0
Acceptance
Range
CCITT Rec. G.823 Limit
0.1
10Hz
100Hz
10kHz
1kHz
Frequency
100kHz
1MHz
Figure 16. MRT Jitter Tolerance at 8.448 Mbit/s
(VDD = 5V, TA = 25oC)
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TXC-02050-MB
Ed. 3, April 1994
MRT
Maximum Output Jitter In Absence of Input Jitter
CCITT Recommendation G.823 specifies that it is necessary to restrict the amount of jitter generated by individual equipments. The actual limits depend on the type of equipment (and application).
In the absence of applied jitter, the receive path of the MRT introduces a maximum 0.05 Unit Intervals (UIs)
peak-to-peak jitter over the following frequency ranges:
At 8.448 Mbit/s: 20 Hz to 400 kHz
At 34.368 Mbit/s: 100 Hz to 800 kHz
This operation is with the MRT terminated by the external components (and component values) specified in
the Pin Description Table for pin 7 (VCOC), pin 17 (PLLC), and pin 22 (AGFIL).
Jitter Transfer
Transfer of jitter through an individual equipment is characterized by the relationship between the applied input
jitter and the resulting output jitter as a function of frequency. CCITT Recommendation G.823 specifies that it is
important to restrict jitter gain.
With applied input jitter at the MRT receive terminals, the maximum MRT output jitter is not greater than the
level of input jitter plus 0.05 UI peak-to-peak jitter.
This operation is over the same CCITT specified frequency ranges and MRT external terminations as
described in the above Maximum Output Jitter section.
Interfering Tone Tolerance
The MRT will properly recover clock and present error-free output to the receive terminal side interface in the
presence of a PRBS interfering tone with the same data sequence as the data input for the following line rates:
Table 3. Interfering Tone Tolerance
Data Rate (Mbit/s)
Tone Rate (Mbit/s)
Maximum Tone Level
Data Sequence
34.368
34.368 ± 100ppm
-18 dB
223-1
8.448
8.448 ± 100ppm
-4 dB
215 - 1
6.312
6.312 ± 100ppm
-4 dB
215 - 1
*PRBS = Pseudo-Random Binary Sequence
- 19 -
TXC-02050-MB
Ed. 3, April 1994
MRT
PACKAGING
The MRT device is packaged in a 44-pin plastic leaded chip carrier suitable for socket or surface mounting. All
dimensions shown are in inches and are nominal unless otherwise noted.
.170
nom.
.650 (nom) SQ.
.500 (nom) SQ.
.075
6
1
.690 (nom) SQ.
.149
nom.
40
40
1
6
.050 typ
7
39
7
39
TRANSWITCH
.015 typ
17
29
18
17
29
28
28
18
BOTTOM VIEW
TOP VIEW
Figure 17. MRT 44-Pin Plastic Leaded Chip Carrier
- 20 -
TXC-02050-MB
Ed. 3, April 1994
MRT
ORDERING INFORMATION
Part Number: TXC-02050-AIPL
44-pin Plastic Leaded Chip Carrier
RELATED PRODUCTS
TXC-03701 E2/E3F Framer VLSI device. The E2/E3 Framer directly interfaces with the MRT
and provides multi-mode framing for CCITT G.751/G.753 (34368 kbit/s) or CCITT G.742/
G.745 (8448 kbit/s) signals.
TXC-03702 JT2F Framer VLSI device. The JT2F Framer directly interfaces with the MRT and
provides framing for CCITT G.704 (6312 kbit/s) signals.
TXC-21055 MRT Evaluation Board. A complete ready-to-use single board that demonstrates
the functions and features of the MRT line interface VLSI device.
- 21 -
TXC-02050-MB
Ed. 3, April 1994
MRT
STANDARDS DOCUMENTATION SOURCES
Telecommunication technical standards and reference documentation may be obtain from
the following organizations:
ANSI (U.S.A.):
American National Standards Institute (ANSI)
11 West 42nd Street
New York, New York 10036
Tel: 212-642-4900
Fax: 212-302-1286
Bellcore (U.S.A.):
Bellcore
Attention - Customer Service
8 Corporate Place
Piscataway, NJ 08854
Tel: 800-521-CORE (In U.S.A.)
Tel: 908-699-5800
Fax: 908-336-2559
CCITT:
Publication Services of ITU
Place des Nations
CH 1211
Geneve 20, Switzerland
Tel: 41-22-730-5285
Fax: 41-22-730-5991
TTC (Japan):
TTC Standard Publishing Group of the
Telecommunications Technology Committee
2nd Floor, Hamamatsucho - Suzuki Building,
1 2-11, Hamamatsu-cho, Minato-ku, Tokyo
Tel: 81-3-3432-1551
Fax: 81-3-3432-1553
- 22 -
TXC-02050-MB
Ed. 3, April 1994
MRT
LIST OF DATA SHEET CHANGES
This change list identifies those areas within the updated MRT Data Sheet that have technical differences relative to the superseded MRT Data Sheet:
Updated MRT Data Sheet:
Edition 3, April 1994
Superseded MRT Data Sheet:
Edition 2, February 1992
The page numbers indicated below of the updated data sheet include changes relative to the superseded data
sheet.
Page Number of
Updated Data Sheet
Summary of the Change
All
Changed edition number and date on all pages.
All
Removed “Preliminary” designation.
2
Changed direction of DI2 pin in Figure 1, Block Diagram.
2-3
Made minor edits to Block Diagram Description.
4
Replaced description of pin 30, DI2.
5
Edited descriptions of pins 5 (LQLTY) and 38 (CLKI).
6
Made minor edits to descriptions of pins 4 (BERCK), 24 (LBKRX) and 25
(LBKTX). Also added Note 1 at bottom of page.
7
Added value for f in description of pins 27 and 28 (EQB1 and EQB0), and
replaced description of pin 7 (VCOC).
8
Added values to first row of Thermal Characteristics table and removed
second row.
11-12
Made minor clarifications to second paragraph of text and to Figures 3, 4,
and 5.
13
Deleted Note 3 below Figure 7.
14
Deleted Note 3 below Figure 9.
15
Made minor changes to Figure 10.
16
Added two sentences to Line Side Input Circuit text.
17
Made minor edits to Figure 13 and to the paragraph of text below it.
17
Made minor changes to Figure 14.
18
Added Jitter Generation paragraph.
18
Changed Jitter Transfer text at bottom of page.
19
Changed Interfering Tone Tolerance text, added the Data Sequence column to Table 3, and removed Table 4.
20
Removed ceramic packaging diagram and added measurements to Figure
17, plastic packaging diagram.
22
Added Standards Documentation Sources.
- 23 -
TXC-02050-MB
Ed. 3, April 1994
MRT
- NOTES -
- 24 -
TXC-02050-MB
Ed. 3, April 1994
MRT
- NOTES -
TranSwitch reserves the right to make changes to the product(s) or
circuit(s) described herein without notice. No liability is assumed as a
result of their use or application. TranSwitch assumes no liability for
TranSwitch applications assistance, customer product design, software performance, or infringement of patents or services described
herein. Nor does TranSwitch warrant or represent that any license,
either express or implied, is granted under any patent right, copyright,
mask work right, or other intellectual property right of TranSwitch covering or relating to any combination, machine, or process in which
such semiconductor products or services might be or are used.
- 25 -
TXC-02050-MB
Ed. 3, April 1994
TranSwitch VLSI:
Powering Communication Innovation
TranSwitch Corporation • 8 Progress Drive • Shelton, CT 06484 • USA • Tel: 203-929-8810 • Fax: 203-926-9453
MRT
DOCUMENTATION UPDATE REGISTRATION FORM
If you would like be added to our database of customers who have registered to receive updated documentation for this device as it becomes available, please provide your name and address below, and fax or mail this
page to Mary Koch at TranSwitch. Mary will ensure that relevant Product Information Sheets, Data Sheets,
Application Notes and Technical Bulletins are sent to you.
Please print or type the information requested below, or attach a business card.
Name: ________________________________________________________________________
Title: _________________________________________________________________________
Company: _____________________________________________________________________
Dept./Mailstop: ________________________________________________________________
Street: _______________________________________________________________________
City/State/Zip: _________________________________________________________________
If located outside U.S.A., please add - Postal Code:
___________ Country: ______________
Telephone:______________________________________________ Ext.: _________________
Fax: __________________________________ E-Mail: _______________________________
Purchasing Dept. Location: _______________________________________________________
Please describe briefly your intended application for this device, and indicate whether you would
care to have a TranSwitch applications engineer contact you to provide assistance:
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
If you are also interested in receiving updated documentation for other TranSwitch device types,
please list them below rather than submitting separate registration forms:
__________
__________
__________
__________
__________
__________
Please fax this page to Mary Koch at (203) 926-9453 or fold, tape and mail it (see other side)
- 27 -
TXC-02050-MB
Ed. 3, April 1994
TranSwitch VLSI:
Powering Communication Innovation
(Fold back on this line second, then tape closed, stamp and mail.)
First
Class
Postage
Required
TranSwitch Corporation
Attention: Mary Koch
8 Progress Drive
Shelton, CT 06484
U.S.A.
(Fold back on this line first.)
Please complete the registration form on this back cover sheet, and fax or mail it, if you
wish to receive updated documentation on this TranSwitch product as it becomes available.
TranSwitch Corporation • 8 Progress Drive • Shelton, CT 06484 • USA • Tel: 203-929-8810 • Fax: 203-926-9453