MT9044AL Zarlink, MT9044AL Datasheet - Page 19

• Manufacturer Part Number: MT9044AL
• Description: Framer E1/OC3/T1 5V 44-Pin MQFP
• Manufacturer: Zarlink

Specifications of MT9044AL

• Package: 44MQFP
• Maximum Data Rate: 2.048 Mbps
• Number Of Transceivers: 1
• Standard Framing Format: E1|OC3|T1
• Maximum Supply Current: 90 mA
• Minimum Single Supply Voltage: 4.5 V
• Maximum Single Supply Voltage: 5.5 V

Applications
This section contains MT9044 application specific details for clock and crystal operation, guard time usage, reset
operation, power supply decoupling, Manual Control operation and Automatic Control operation.
Master Clock
The MT9044 can use either a clock or crystal as the master timing source.
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 ±100 ppm. For applications requiring an accurate Freerun Mode, such as Bellcore GR-1244-CORE, the
tolerance of the master timing source must Be no greater than ±32 ppm.
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 MT9044 will always equal ±230 ppm.
For example, if the master timing source is ±100 ppm, then the capture range will be ±130 ppm.
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.
See AC Electrical Characteristics.
For applications requiring ±32 ppm clock accuracy, the following clock oscillator module may be used.
CTS CXO-65-HG-5-C-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 MT9044, 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 10.
20 MHz
25 ppm 0C to 70C
8 ns (0.5 V 4.5 V 50 pF)
45% to 55%
MT9044
Figure 9 - Clock Oscillator Circuit
OSCo
OSCi
No Connection
Zarlink Semiconductor Inc.
MT9044
20 MHz OUT
19
+5 V
+5 V
GND
0.1 uF
Data Sheet