MT9075B Mitel Networks Corporation, MT9075B Datasheet - Page 9

• Manufacturer Part Number: MT9075B
• Description: E1 Single Chip Transceiver
• Manufacturer: Mitel Networks Corporation

Preliminary Information
The template for the transmitted pulse, as specified in
G703, is shown in Figure 5. The nominal peak voltage
of a mark is 3 volts for 120
and 2.37 volts for 75
the amplitude of the transmit pulses generated by TTP
and TRING is between 0.95 and 1.05.
Transformer Recommendation
Table 1 shows a list of recommended transformers
for the MT9075B line interface.
Percentage of
Nominal Peak
120
110
100
-10
-20
50
10
90
80
0
MT9075B
TRING
RRING
TTIP
RTIP
Figure 4 - Analog Line Interface
Figure 5 - Pulse Template (G.703)
0.68uF
coax applications. The ratio of
R
R
120
T
T
269nS
244nS
194nS
219nS
488nS
twisted pair applications
* 2.4
required with 75
1:2
1:1
resistors are only
Nominal Pulse
Rx
coax
Tx
Timing Source
The MT9075B can use either a clock or crystal,
connecting to pins OSC1 and OSC2, as the
reference timing source.
Figure 6 shows a 20MHz clock oscillator, with 50ppm
tolerance, directly connected to the OSC1 pin of the
MT9075B.
Alternatively, a crystal oscillator may be used. A
complete oscillator circuit made up of a crystal,
resistors and capacitors is shown in Figure 7. The
crystal specification is as follows.
Frequency:
Tolerance:
Oscillation Mode:
Resonance Mode:
Load Capacitance:
Maximum Series Resistance:
Approximate Drive Level:
Table 1 - Transformer Manufacturers and Part
Pulse Engineering
Manufacturer
MT9075B
Midcom
Figure 6 - Clock Oscillator Circuit
OSEC
Filtran
OSC1
OSC2
Numbers
(
open
PE-65351
02934/A
5721-1
20MHz
For Tx
50027
OUT
)
+
5V
GND
MT9075B
Vdd
20MHz
50ppm
Fundamental
Parallel
32pF
35
1mW
PE-64934
02935/A
For Rx
5721-2
50026
.1 F
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