MSTM-S3-IT3-19.44M Datasheet, PDF (2/16 Pages) Connor-Winfield Corporation – Stratum 3 Timing Module

General Description
The Connor-Winfield Stratum 3 Simplified Control Timing
Module acts as a complete system clock module for general
Stratum 3 timing applications.
Full external control input allows for selection and monitoring
of any of four possible operating states: 1) Holdover, 2) External
Reference #1, 3) External Reference #2, and 4) Free Run. Table
#1 illustrates the control signal inputs and corresponding opera-
tional states.
In the absence of External Control Inputs (A,B), the MSTM
enters the Free Run mode and signals an External Alarm. The
MSTM will enter other operating modes upon application of a
proper control signal. Mode 1 operation (A=1, B=0) results in an
output signal that is phase locked to the External Reference
Input #1. Mode 2 operation (A=0, B=1) results in an output sig-
nal that is phase locked to External Reference Input #2. Hold-
over mode operation (A=1, B=1) results in an output signal at or
near the frequency as determined by the latest (last) locked-
signal input values and the holdover performance of the MSTM.
Free Run ModeFree Run mode operation (A=0, B=0) is a guar-
anteed output of 4.6 ppm of the nominal frequency.
Alarm signals are generated at the Alarm Output during Hold-
over and Free Run operation. Alarm Signals are also generated
by loss-of-lock, loss of Reference, and by a Tune-Limit indication
from the PLL. A Tune-Limit alarm signal indicates that the
OCXO tuning voltage is approaching within 10% the limits of its
lock capability and that the External Reference Input may be
erroneous. A high level indicates an alarm condition. Real-time
indication of the operational mode is available at unique operat-
ing mode outputs on pins 1-4.
Control loop 0.1 Hz filters effectively attenuate any reference
jitter, smooth out phase transients, comply with wander transfer
and jitter tolerances.
Functional Block Diagram
Figure 1
CNTL A
CNTL B
Mode
Control
Reference
Select
Ex Ref 1
Ex Ref 2
Free Run
Ref 1
Ref 2
Holdover
PLL TVL
Free Run
Holdover
Phase
Comparator
LOL/LOR
DAC
Filters
DAC
Tuning
Voltage
Monitor
FIFO
PLL TVL
Stratum
3
OCXO
Alarm Out
SYNC_OUT
Table 1
CNTL
A
0
1
0
1
Function Control Table
CNTL
B
0
0
1
1
Operational
Mode
Free Run (Default Mode)
External
Reference
#1
Normal
Tune Limit
LOR + LOL
External
Reference
#2
Normal
Tune Limit
LOR + LOL
Hold Over
Ref 1
0
1
1
1
0
0
0
0
Ref 2 Hold Over Free Run
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
1
0
0
0
1
0
PLL_TVL Alarm Out
0
1
0
0
1
1
0
1
0
0
1
1
0
1
0
1
Table 2
Symbol
V_CC
V_I
T_s
Parameter
Power Supply Voltage
Input Voltage
Storage Temperature
Absolute Maximum Rating
Minimum
-0.5
-0.5
-55
Nominal
Maximum
7.0
V_CC + 0.5
100
Units
Volts
Volts
deg. C
Notes
1.0
1.0
1.0
Data Sheet #: TM034 Page 2 of 16 Rev: P01 Date: 12 / 04 / 02
© Copyright 2002 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice