MT9074
Percentage of
Nominal Peak
Voltage
120
110
100
90
80
50
269nS
244nS
194nS
Advance Information
20
0
-10
Nominal Pulse
-20
219nS
488nS
Figure 8 Pulse Template (G.703)(E1)
20 Mhz Clock
The MT9074 requires a 20 Mhz clock. This may
provided by a 50 ppm oscillator as per Figure 9.
+5V
Frequency:
Tolerance:
Oscillation Mode:
Resonance Mode:
Load Capacitance:
Maximum Series Resistance:
Approximate Drive Level:
OSC1
20MHz
OUT
Vdd
GND
.1µF
OSC1
20MHz
50ppm
Fundamental
Parallel
32pF
35Ω
1mW
20MHz
OSC2
(open)
Figure 9 - Clock Oscillator Circuit
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.
1MΩ
OSC2
56pF
39pF
100Ω
1µH*
Note: the 1µH inductor is optional
Figure 10 - Crystal Oscillator Circuit
12