MT9044AL Zarlink, MT9044AL Datasheet - Page 21

• 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

A simple way to control the guard time (using Automatic Control) is with an RC circuit as shown in Figure 11.
Resistor R
guard time can be calculated as follows.
•
In cases where fast toggling might be expected of the LOS1 input, then an unsymmetrical Guard Time Circuit is
recommended. This ensures that reference switching doesn’t occur until the full guard time value has expired. An
unsymmetrical Guard Time Circuit is shown in Figure 12.
V
SIH
is the logic high going threshold level for the GTi Schmitt Trigger input, see DC Electrical Characteristics
P
is for protection only and limits the current flowing into the GTi pin during power down conditions. The
Figure 12 - Unsymmetrical Guard Time Circuit
Figure 11 - Symmetrical Guard Time Circuit
MT9044
MT9044
guard time
guard time
example
guard time 150k 10u
GTo
GTo
GTi
GTi
Zarlink Semiconductor Inc.
≈
≈
MT9044
=
150 kΩ
150 kΩ
RC
1 kΩ
RC
R
R
R
C
D
21
×
×
×
0.6
1 kΩ
ln
R
1 kΩ
R



P
--------------------------------
V DD V SIH
P
×
+
0.6
V DD
10 uF
–
=
C
1.45
10 uF
C
s



+
Data Sheet