MT9074AL Zarlink Semiconductor, Inc., MT9074AL Datasheet - Page 13

• Manufacturer Part Number: MT9074AL
• Description: T1/E1/J1 Single Chip Transceiver
• Manufacturer: Zarlink Semiconductor, Inc.

MT9074
20 Mhz Clock
The MT9074 requires a 20 Mhz clock. This may
provided by a 50 ppm oscillator as per Figure 9.
Alternatively, a crystal oscillator may be used. A
complete oscillator circuit made up of a crystal,
resistors and capacitors is shown in Figure 10. The
crystal specification is as follows.
13
Figure 9 - Clock Oscillator Circuit
OSC1
OSC2
Percentage of
Nominal Peak
Voltage
(
open
20MHz
120
110
100
-10
-20
OUT
90
80
50
20
0
)
+
Figure 8 Pulse Template (G.703)(E1)
5V
GND
Vdd
.1µF
269nS
244nS
194nS
219nS
488nS
Frequency:
Tolerance:
Oscillation Mode:
Resonance Mode:
Load Capacitance:
Maximum Series Resistance:
Approximate Drive Level:
Figure 10 - Crystal Oscillator Circuit
Nominal Pulse
OSC2
OSC1
1MΩ
Note: the 1µH inductor is optional
56pF
20MHz
100Ω
Data Sheet
20MHz
50ppm
Fundamental
Parallel
32pF
35Ω
1mW
39pF
1µH*