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Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module
1.0 DESCRIPTION AND APPLICATION The VCT1000B is a hitless-switching dual-input stratum 3 low jitter timing module with status outputs and alarms. Dual 8 kHz references are independently selected to lock a digital phase lock loop resulting in excellent long and short-term stability. Two control inputs are used to steer the state machine decisions for the operation of the module. The state machine will enter and maintain the operation in the free run, holdover, or locked condition. The state machine operates under the requirements of section 3.4 of the Telcordia GR-1244-CORE. Four status pins indicate the condition, which the unit is operating, and two alarm outputs indicate the loss of lock and holdover or free run operation. The signal outputs are the low jitter oscillator output and the divided 8kHz output. Input phase rearrangement allows the output to remain hitless upon the switching of the references, regardless of input phase. Dimensions are 2" x 2" x 0.55". A state machine is used to assure that switching to a bad reference is not allowed, and that both references are qualified.
CNTL A CNTL B
System Control and State Machine
Ref 1 Ref 2 Free Run Holdover
Main Status Alarm
Alarm Out Loss of Lock Alarm
System control lines to all blocks Divider Buffer 8 kHz Output
REF 1 8 kHz
Input Buffer Phase Alignment Reference Qualification
Hitless Switching MUX
Phase Detector Buffer 19.440 MHz Output
REF 2 8 kHz
Input Buffer Phase Alignment Reference Qualification
Divider
Holdover History and Digital Filtering Stratum III OCXO DAC
Figure 1 VCT1000B Block Diagram
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Rev. "5" 1/20/04
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module
2.0
2.1 2.2
ELECTRICAL CHARACTERISTICS
Specification Regulated Input Supply Voltage, Vcc Supply Current Drain... At turn-on Steady state Current @ 25C Frequency Output (at pin 11) Temperature Ranges Operating Temp. Range Storage Temp. Range Timing Parameters Jitter Generation and transfer Jitter Tolerance (see Figure 2) Wander Tolerance (See figure 3) Wander Generation TDEV (see Figure 4) MTIE (see Figure 5 and 6) Holdover Frequency accuracy (for the initial 24 hours during holdover) Free-run Accuracy (under all conditions) Holdover History Correction period Lock time Input Logic Levels ` 0' `1' Output Logic Levels `0' `1' Module tuning range Dual Reference input Output loads Output Signal Rise-time 19.440 Min 4.75 Typ 5.00 Max 5.25 Units V DC
550 250
mA mA MHz
2.3 2.4 2.4.1 2.4.2 2.5 2.5.1 2.5.2 2.5.3 2.5.4 2.5.5 2.5.6 2.5.7 2.5.8 2.5.9 2.5.10 2.6 2.6.1 2.6.2 2.7 2.7.1 2.7.2 2.7 2.8 2.9 2.10
0 -40
70 85
C C
-0.05
0.05
UI
-0.37 -4.6 30 40 60
0.37 4.6 125 90
ppm ppm sec usec sec
-0.5 2.4
0.8 5.5
V V
-0.25 4.0 -9.2 -4.6
0.8 Vcc*0.9 9.2 4.6 30 3
V V ppm ppm pF n sec
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Rev. "5" 1/20/04
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module
Figure 2 Jitter Input Tolerance
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Rev. "5" 1/20/04
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module
Figure 3
Wander Input Tolerance
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Rev. "5" 1/20/04
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module
Figure 4 Wander Generation
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Rev. "5" 1/20/04
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module
Figure 5 MTIE for Wander Generation
Figure 6 MTIE for Rearrangement
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Rev. "5" 1/20/04
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module 3.0 MECHANICAL CHARACTERISTICS 3.1 Pkg. size is 2 in (50.80 mm) X 2 in (50.80 mm) X 0.56 in (14.22mm) max. 18 pin DIP style.
Figure 6 VCT1000B Outline
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Rev. "5" 1/20/04
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module VCT1000B Pin Functions
Pin # 1 2 3 4 6 7 8 9 5,10,12, 14,16 18 11 13 17 15 Name HOLDOVER REF 1 REF 2 FREERUN ALARM OUT CNTL A CNTL B PLL UNLOCK GND +5V OUT OPT OUT EX REF 1 EX REF 2 Description Holdover Signal -> the output is high when the unit is in holdover mode Reference 1 Signal -> the output is high when the unit is using the reference 1 Reference 2 Signal -> the output is high when the unit is using the reference 2 Free-run Signal -> the output is high when the unit is in the free run mode Alarm signal -> the output is high when there is an alarm in the module, alarm condition is during free-run mode, holdover mode, Control Input 1 -> the external input for selecting mode of the unit - see table. Control Input 2 -> the external input for selecting mode of the unit - see table. PLL Unlocked Signal -> the output is high when the unit is not locked to any of the references Ground Positive Voltage Supply Synchronized Output -> the output of the synchronized signal Optional Output -> the secondary output of the synchronized signal, Pre-defined as OUT/N where N is a integer External Reference 1 Input -> the input signal from reference 1 External Reference 2 Input -> the input signal from reference 2
Control Functions
CNTL B 0 0 1 1 CNTL A 0 1 0 1 MODE OF OPERATION Free-run Locked to REF1 Locked to REF2 Holdover
4.0
STANDARD ENVIRONMENTAL LIMITS
This product is capable of operating within the following environmental conditions: 4.1 Operating Temperature 4.2 Storage Temperature 4.3 Humidity (non- Condensing) 4.4 Atmospheric Pressure 4.5 Vibration 0 to +70 C. -40 to +85C. 95% Relative humidity max @ 40C. 730 to 780 mm Hg. 10 to 60 Hz with double amplitude of 1.52mm max. (1/2 hour in each of 3 perpendicular planes). 1/2 sine pulse, 7000G, with pulse width 0.3mSec. (1 shock in each of 6 directions of 3 perpendicular planes).
4.6 Shock
5.0
MAXIMUM SOLDERING PROFILE Temperature Time 110 to150 C 6min >183C 2.5min >235C 0.25min 240C Max temperature
Rev. "5" 1/20/04
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