MT9040AN Zarlink Semiconductor, MT9040AN Datasheet - Page 10

• Manufacturer Part Number: MT9040AN
• Description: Description = Single Reference Frequency Selectable, 3.3V Digital PLL With Multiple Clock Outputs For Stratum 4 Applications ;; Package Type = Ssop ;; No. Of Pins = 48
• Manufacturer: Zarlink Semiconductor

In Freerun Mode, the frequency tolerance at the clock outputs is identical to the frequency tolerance of the source
at the OSCi pin. For applications not requiring an accurate Freerun Mode, tolerance of the master timing source
may be
the master timing source must be no greater than
Another consideration in determining the accuracy of the master timing source is the desired capture range. The
sum of the accuracy of the master timing source and the capture range of the MT9040 will always equal 230ppm.
For example, if the master timing source is 100ppm, then the capture range will be 130ppm.
Clock Oscillator - when selecting a Clock Oscillator, numerous parameters must be considered. This includes
absolute frequency, frequency change over temperature, output rise and fall times, output levels and duty cycle.
For applications requiring
FOX F7C-2E3-20.0MHz
Frequency:
Tolerance:
Rise & Fall Time:
Duty Cycle:
CTS CB3LV-5I-20.0 MHz
Frequency:
Tolerance:
Rise & Fall Time:
Duty Cycle:
The output clock should be connected directly (not AC coupled) to the OSCi input of the MT9040, and the OSCo
output should be left open as shown in Figure 9.
Crystal Oscillator - Alternatively, a Crystal Oscillator may be used. A complete oscillator circuit made up of a
crystal, resistor and capacitors is shown in Figure 6.
±
100ppm. For applications requiring an accurate Freerun Mode, such as AT&T TR62411, the tolerance of
20MHz
25ppm 0C to 70C
10ns (0.33V 2.97V 15pF)
20MHz
25ppm
10ns
40% to 60%
45% to 55%
±
32ppm clock accuracy, the following clock oscillator module may be used.
Figure 5 - Clock Oscillator Circuit
MT9040
OSCo
OSCi
No Connection
Zarlink Semiconductor Inc.
±
MT9040
32ppm.
20MHz OUT
+3.3V
+3.3V
10
GND
0.1uF
Data Sheet