MT9044AL Zarlink, MT9044AL Datasheet - Page 22

• 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

Figure 13 shows a typical timing example of an unsymmetrical Guard Time Circuit with the MT9044 in Automatic
Control.
TIE Correction (using GTi)
When Primary Holdover Mode is entered for short time periods, TIE correction should not be enabled. This will
prevent unwanted accumulated phase change between the input and output. This is mainly applicable to Manual
Control, since Automatic Control together with the Guard Time Circuit inherently operate in this manner.
For instance, 10 Normal to Holdover to Normal mode change sequences occur, and in each case Holdover was
entered for 2s. Each mode change sequence could account for a phase change as large as 350 ns. Thus, the
accumulated phase change could be as large as 3.5 us, and, the overall MTIE could be as large as 3.5 us.
•
•
•
When 10 Normal to Holdover to Normal mode change sequences occur without MTIE enabled, and in each case
holdover was entered for 2s, each mode change sequence could still account for a phase change as large as
350 ns. However, there would be no accumulated phase change, since the input to output phase is re-aligned after
every Holdover to Normal state change. The overall MTIE would only be 350 ns.
0.05 ppm is the accuracy of Holdover Mode
50 ns is the maximum phase continuity of the MT9044 from Normal Mode to Holdover Mode
200 ns is the maximum phase continuity of the MT9044 from Holdover Mode to Normal Mode (with or without TIE
Corrector Circuit)
NOTES:
1. T
bad to when the MT9044 is provided with a LOS indication.
D
MT9044
STATE
STATUS
STATUS
SIGNAL
SIGNAL
represents the time delay from when the reference goes
SEC
PRI
LOS2
LOS1
GTo
GTi
Figure 13 - Automatic Control, Unsymmetrical Guard Time Circuit Timing Example
V
NORMAL
SIH
GOOD
PRI
HOLDOVER
T
BAD
D
Phase hold
Phase state
Phase 10
PRI
Zarlink Semiconductor Inc.
=
NORMAL
GOOD
=
=
10
PRI
MT9044
0.05ppm
50ns
×
(
250ns
GOOD
22
+
200ns
HOLDOVER
T
×
+
D
2s
100ns
PRI
=
=
250ns
100ns
)
=
BAD
3.5us
NORMAL
SEC
NORMAL
GOOD
PRI
Data Sheet