VCT1000B CTS | Alldatasheet
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Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module Page 1 of 8 Rev. “5” 1/20/04
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. Figure 1 VCT1000B Block Diagram System Control and State Machine Main Status Alarm Ref 1 Ref 2 Free Run Holdover Input Buffer Phase Alignment Reference Qualification Input Buffer Phase Alignment Reference Qualification Hitless Switching MUX Phase Detector Holdover History and Digital Filtering DAC Divider Stratum III OCXO Buffer Buffer Divider System control lines to all blocks CNTL A CNTL B REF 1 8 kHz REF 2 8 kHz Alarm Out Loss of Lock Alarm 8 kHz Output 19.440 MHz Output
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module Page 2 of 8 Rev. “5” 1/20/04
2.0 ELECTRICAL CHARACTERISTICS
Specification Min Typ Max Units 2.1 Regulated Input Supply Voltage, Vcc 4.75 5.00 5.25 V DC
2.2 Supply Current Drain…
Steady state Current @ 25C 250 mA 2.3 Frequency Output (at pin 11) 19.440 MHz
2.4 Temperature Ranges
2.4.1 Operating Temp. Range 0 70 ºC 2.4.2 Storage Temp. Range -40 85 ºC
2.5 Timing Parameters
2.5.1 Jitter Generation and transfer -0.05 0.05 UI
2.5.2 Jitter Tolerance (see Figure 2)
2.5.3 Wander Tolerance (See figure 3)
2.5.4 Wander Generation TDEV (see Figure 4)
2.5.5 MTIE (see Figure 5 and 6)
2.5.6 Holdover Frequency accuracy (for the initial 24 hours
during holdover) -0.37 0.37 ppm 2.5.7 Free-run Accuracy (under all conditions) -4.6 4.6 ppm
2.5.8 Holdover History 30 sec
2.5.9 Correction period 125 usec
2.5.10 Lock time 40 60 90 sec
2.6 Input Logic Levels
2.7 Output Logic Levels
2.7 Module tuning range -9.2 9.2 ppm 2.8 Dual Reference input -4.6 4.6 ppm
2.9 Output loads 30 pF
2.10 Output Signal Rise-time 3 n sec
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module Page 3 of 8 Rev. “5” 1/20/04 Figure 2 Jitter Input Tolerance
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module Page 4 of 8 Rev. “5” 1/20/04 Figure 3 Wander Input Tolerance
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module Page 5 of 8 Rev. “5” 1/20/04 Figure 4 Wander Generation
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module Page 7 of 8 Rev. “5” 1/20/04
3.0 MECHANICAL CHARACTERISTICS
max. 18 pin DIP style. Figure 6 VCT1000B Outline
Stratum III Timing Module : VCT1000B Application: Dual Input Timing Module Page 8 of 8 Rev. “5” 1/20/04 VCT1000B Pin Functions Pin # Name Description
1 HOLDOVER Holdover Signal -> the output is high when the unit is in holdover mode
2 REF 1 Reference 1 Signal -> the output is high when the unit is using the reference 1
3 REF 2 Reference 2 Signal -> the output is high when the unit is using the reference 2
4 FREERUN Free-run Signal -> the output is high when the unit is in the free run mode
6 ALARM OUT Alarm signal -> the output is high when there is an alarm in the module, alarm
condition is during free-run mode, holdover mode, 7 CNTL A Control Input 1 -> the external input for selecting mode of the unit – see table. 8 CNTL B Control Input 2 -> the external input for selecting mode of the unit – see table.
9 PLL UNLOCK PLL Unlocked Signal -> the output is high when the unit is not locked to any of the
5,10,12, 14,16 GND Ground 18 +5V Positive Voltage Supply
11 OUT Synchronized Output -> the output of the synchronized signal
13 OPT OUT Optional Output -> the secondary output of the synchronized signal, Pre-defined as
OUT/N where N is a integer
17 EX REF 1 External Reference 1 Input -> the input signal from reference 1
15 EX REF 2 External Reference 2 Input -> the input signal from reference 2
CNTL B CNTL A MODE OF OPERATION 0 0 Free-run 0 1 Locked to REF1 1 0 Locked to REF2 1 1 Holdover
4.0 STANDARD ENVIRONMENTAL LIMITS
This product is capable of operating within the following environmental conditions: 4.1 Operating Temperature 0 to +70 °C. 4.2 Storage Temperature -40 to +85 °C. 4.3 Humidity (non- Condensing) 95% Relative humidity max @ 40 °C. 4.4 Atmospheric Pressure 730 to 780 mm Hg.
4.5 Vibration 10 to 60 Hz with double amplitude of
1.52mm max. (1/2 hour in each of 3 perpendicular planes).
4.6 Shock 1/2 sine pulse, 7000G, with pulse width
0.3mSec. (1 shock in each of 6 directions of 3 perpendicular planes).
5.0 MAXIMUM SOLDERING PROFILE
Temperature 110 to150 °C >183 °C >235°C 240 °C Time 6min 2.5min 0.25min Max temperature