Microsemi SA.22c User Manual
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Microsemi SA.22c User Manual

Microsemi SA.22c User Manual

Rubidium oscillator
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Designer Reference and User Guide
SA.22c Rubidium Oscillator

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Summary of Contents for Microsemi SA.22c

  • Page 1 Designer Reference and User Guide SA.22c Rubidium Oscillator...

  • Page 2: Table Of Contents

    SA.22c Rubidium Oscillator Contents 1 Revision History ..........................1 1.1 Revision D ............................1 1.2 Revision C ............................1 1.3 Revision B ............................1 1.4 Revision A ............................1 2 Overview ............................2 2.1 Applications ............................2 2.2 Specifications ............................4 3 Design Integration Considerations ....................
  • Page 3 5.2 Interfacing the Adapter Test Board ....................17 5.3 Options for Supplying Power to the Adapter Test Board ..............19 6 Appendix: Microsemi Serial Interface Protocol ................25 6.1 Using the Microsemi Serial Interface Protocol ................. 25 6.1.1 Host Terminal Emulator Setup ......................25 6.1.2...

  • Page 4: Revision History

    Revision B was published in February 2017. The following is a summary of the changes in revision B of this document. The SA.22c Dimensions diagram was updated. The SA-22c or X72 Refresh Output Control Register table was included. Revision A Revision A was the first publication of this document.

  • Page 5: Overview

    SA.22c oscillator continues to produce a stable and accurate time along with a frequency reference. The SA.22c can be integrated into time and frequency systems, it operates on low power (10 W at 25 °C, operating).
  • Page 6 Appendix: One Pulse Per Second Source Connection (see page 30) For simple applications, the SA.22c provides a 5 V CMOS-compatible built-in self test (BIST) service and a lock alarm signal derived from the basic physics operation. The lock signal indicates when the output frequency is locked to the atomic resonance of rubidium.

  • Page 7: Specifications

    Figure 3 • SA.22c Dimensions Note: The mating connector is a SAMTEC TMMH-109-01-G-DV-ES-A 2 X 9 shrouded header. Caution: To avoid damage to the SA.22c, ensure that power and ground are properly connected. Note: All pins on the I/O connector must be connected.
  • Page 8 Appendix: Using the Developer’s Kit (see page 16) The following table provides information on the absolute maximum ratings for the SA.22c design. Note: Unit in ambient still air convection (–10 °C to 75 °C). Table 2 • SA.22c Design Absolute Maximum Ratings...
  • Page 9 SA.22c Rubidium Oscillator The following tables provides information on the operating characteristics for SA.22c design. Note: Unit in ambient still air convection (–10 °C to 75 °C). Table 3 • SA.22c Design Operating Characteristics Symbol Characteristic and Condition Minimum Typical...
  • Page 10 SA.22c Rubidium Oscillator The following figure shows the typical values for total quiescent power dissipation of SA.22c. Figure 4 • Total SA.22c Quiescent Power Dissipation, Typical (free convection) The following figure shows the typical API level. Figure 5 • Typical AP1 Level Tempco (–10 °C to 75 °C Base Plate Temperature) Note: For more information, see SA.22c Performance Characteristics.

  • Page 11: Design Integration Considerations

    Microsemi sales representatives. The following figure shows how to mount SA.22c to a circuit board. Mount the SA.22c to the circuit board using six M3 stainless steel screws with a minimum penetration depth of 2 mm and a maximum of 5 mm.

  • Page 12: Water Condensation And Excessive Humidity

    If the lock signal is high, the atomic lock is lost and the SA.22c goes into sweep mode to reacquire lock. The sweep ranges from approximately –21 ppm to 21 ppm in a 20-second period approximately. During the sweep, outputs are maintained but signal accuracy should not be relied upon during sweeping.

  • Page 13: Frequency Control Signal

    Frequency Control Signal The SA.22c frequency control signal is an analog input between 0 Vdc and 5 Vdc that is enabled or disabled at the factory (making it a default setting) or by the customer at a later date (using the MSIP).

  • Page 14: Reliability And Maintenance

    3.7.1 Reliability The SA.22c is designed with a life of ten years of operation without retuning. To accomplish this, the major mechanisms impacting the need for maintenance were addressed. Thus, each SA.22c is designed to have excess rubidium filled in the lamp to last for the required period, sufficient pulling range for the voltage controlled crystal oscillator, and sufficient dynamic range of the rubidium control loop.

  • Page 15: Installation And Operation

    The following sections provide general installation advice. 4.1.1 Site Selection The SA.22c can be mounted in any orientation. Ensure that the temperature limits are not exceeded for the proper functioning of the SA.22c. The SA.22c is sensitive to external DC and AC magnetic fields (see,...

  • Page 16: Start-Up Sequence

    Note: Signals appear at the outputs immediately after power is applied to the unit, but these output signals are not stable until the oscillator is locked. After 7.5 minutes, the accuracy of the SA.22c oscillator is <1 × 10 . Performance of the SA.22c unit –9 varies according to the application profile specified at the time of order.

  • Page 17: Theory Of Operation

    Repairs and Support The SA.22c is not field repairable, but some firmware upgrades can be done in the field, as mentioned in Start-Up Sequence (see page 13) . If the unit fails, do not remove the cover of the unit and attempt to make repairs.

  • Page 18: Email

    3870 N, First Street San Jose, CA 95134 Telephone: 408-428-7907 Toll-free in North America: 1-888-367-7966 4.5.2.2 Europe, Middle East, and Africa (EMEA) Microsemi FTD Services and Support EMEA Altlaufstrasse 42 Hoehenkirchen-Siegertsbrunn 85635 Germany Telephone: +49 700 3288 6435 Fax: +49 8102 8961 533...

  • Page 19: Appendix: Using The Developer's Kit

    Note: The mounting screws of the SA.22c are metric (not SAE) and are 3 mm in length with a 0.5 mm thread pitch. They must not penetrate more than 3 mm into the SA.22c base plate.

  • Page 20: Interfacing The Adapter Test Board

    The following figure shows the mounting of the SA.22c on the adapter test board and to the optional heat sink. Six 10 mm screws are required to properly mount the SA.22c with the adapter test board on the optional heat sink.
  • Page 21 SA.22c Rubidium Oscillator The following table provides information on the pin assignment and the function chart for SA.22c. Table 5 • 18-Pin Samtec I/O Connector (J1) Signal Type Function Power and signal return ground (all ground pins must be connected)

  • Page 22: Options For Supplying Power To The Adapter Test Board

    Output Sine signal output (50 ?) J3, J4, J5, and J6 are SMA connectors used for signal outputs (J4 is a signal input) provided by the SA.22c. The following table lists the SMA connectors' signal information. Table 7 • SMA Connectors' Signal Information...
  • Page 23 Figure 13 • Block Diagram of Suggested Test SA.22C Set-up (Option 1) After the SA.22c unit receives power, wait for a few minutes while the unit achieves atomic lock. During this period, the monitored lock signal must be HIGH. After the unit achieves atomic lock, the lock signal goes LOW.
  • Page 24 It is recommended to power up 5 V first, or simultaneous with the 15 V supply. After the SA.22c unit receives power, wait for a few minutes while the unit achieves atomic lock. During this period, the monitored lock signal should be HIGH. After the unit achieves atomic lock, the lock signal goes LOW.
  • Page 25 Figure 15 • Block Diagram of Suggested Test SA.22C Set-up (Option 3) After the SA.22c unit receives power, wait for few a minutes while the unit achieves atomic lock. During this period, the monitored lock signal must be HIGH. After the unit achieves atomic lock, the lock signal goes LOW.
  • Page 26 SA.22c Rubidium Oscillator Figure 16 • Power Supply and Output Options Option 1 allows you to directly power the adapter test board with 10 Vdc to 32 Vdc supplied to E1 and Designer Reference and User Guide Revision D...
  • Page 27 (J2). TB1 is installed and TB2 and TB3 are open. In the adapter board, this voltage travels through a DC-to-DC converter and a voltage regulator to supply the SA.22c with 15 Vdc and 5 Vdc for operation. For this option, J7 or J2 is used for serial interface communications, J2 is also used for input and output signals.

  • Page 28: Appendix: Microsemi Serial Interface Protocol

    SA.22c outputs are all decimal data as ASCII coded hex except for the echoed characters. Do not convert data to decimal when transmitting to the SA.22c. All data are sent to the SA.22c and received back as ASCII coded hex .
  • Page 29 989680.00000000hz Ctl Reg: 004C, Res temp off: BFC53F7D., Lamp temp off: BFF92B93. FC: disabled, Srvc: high Command h: The following example shows the response to the command h for the SA.22c help menu: r>h a: Set FC Mode f: Adjust DDS Frequency (delta e-11)
  • Page 30 <cr> enables the FC mode. r>a 5987717 FC mode enabled Command p: The following example shows the response to the command p for the SA.22c control register r>p Control Reg: 204C Note: For the above example, C corresponds to bits 12-15, 4 corresponds to bits 8-11, 0 corresponds to bits 4-7, and 2 corresponds to bits 0-3 in the following table.

  • Page 31: Factory Mode

    6.1.3 Factory Mode Data output from the SA.22c in factory mode is not intended for users outside the factory and is not described in this document beyond the table Run Mode Commands (see page 28) Caution: Using factory mode results in the erasure of firmware on the SA.22c rendering it inoperable and making it necessary to return the unit to the factory for re-programming.
  • Page 32 Note: Run mode and admin mode allow the loading of new code, updates, or reconfiguring defaults in the field. It is not a normal operating mode. Table 12 • SA.22c Administrative Mode Commands User Output to SA.22c Response to Host...

  • Page 33: Appendix: One Pulse Per Second Source Connection

    1PPS input and the 1PPS generated internally by the SA.22c. The j command generates a number representing the number of TICS in a delta register. If the SA.22c has a 60 MHz crystal, each TIC is 16.7 ns (1.67×10 ). This number is in hex format.

  • Page 34: System Requirements

    SA.22c Rubidium Oscillator The test bench setup configuration allows the SA.22c to be disciplined by the incoming 1PPS signal. The following figure Test Bench Setup shows the test bench setup. The 1PPS disciplining mode is enabled by default. It can be temporarily disabled by issuing the g command followed by a 1 (see...

  • Page 35: 1Pps Algorithm Operation

    SA.22c input pin or drive the SA.22c high impedance directly with a low impedance source such as 50 Ω or any ACMOS gate as long as the input voltage level at the SA.22c pin is met as described above.

  • Page 36: Changing The Y Coefficients

    SA.22c Rubidium Oscillator 1pps mode is enabled r> Note: It is not necessary for the SA.22c to be locked to enter the 1PPS configuration commands, but it must be locked for actual synchronization to occur. 7.6.1 Changing the y Coefficients Follow the steps to change the y coefficients At the r>...

  • Page 37: The G Command

    There are two types of 1PPS customer firmware. The 1PPS standard firmware provides an Rb or Rb/1PPS lock indicator at pin 14 and a service indicator on pin 12 of the SA.22c I/O connector. The 1PPS LED firmware uses the same functions for pin 14, but pin 12 is reserved for 1PPS lock indication only. There is no service pin on the 1PPS LED versions.

  • Page 38: Flywheeling Recovery Example-Normal

    Pin12 is reserved for 1PPS lock indication only Flywheeling Recovery Example–Normal In this test, the SA.22c is synchronized to 1PPS before the following data set as shown in the following figure. Antenna is removed at 0 hour and reapplied at approximately 12.5 hours. The SA.22c 1PPS output signal reaches an offset of 220 ns.

  • Page 39: Recovery With Jamsynch

    Recovery with JamSynch In this test, the antenna to the GPS receiver is removed. The SA.22c is set to an off frequency long enough to induce a 1PPS error over 1 μsec. When the antenna is reapplied, the SA.22c 1PPS recovers by resetting to 1PPS 0 ns (JamSynch).

  • Page 40: 1Pps Algorithm High Level Flow Chart

    SA.22c Rubidium Oscillator 7.9.1 1PPS Algorithm High Level Flow Chart The following flow chart explains the 1PPS steer algorithm. Figure 21 • SA.22c 1PPS Algorithm States Designer Reference and User Guide Revision D...

  • Page 41: Initialization

    (DF). The SA.22c checks for 1PPS input once per second, and if present, it enters the holdover state. Automatic mode is used when the time constant is set to 0. The SA.22c 1PPS is in the initialization state when no 1PPS is applied. The j command shows the 1PPS count.

  • Page 42: Holdover

    Holdover During holdover, 1PPS input statistics are accumulated and the results are calculated periodically (CalcSlope State). The sample size is set to 120 data points (120 s). Figure 23 • SA.22c Holdover State Designer Reference and User Guide Revision D...

  • Page 43: Calcslope

    SA.22c Rubidium Oscillator 7.9.4 Calcslope The frequency difference between the SA.22c and the 1PPS source is calculated, and if the difference is <±3 × 10 , the state changes from holdover to JamSynch. This state executes every 120 s during –9 holdover.

  • Page 44: Jamsynch

    7.9.5 JamSynch The SA.22c 1PPS output is compared to the SA.22c 1PPS input, and if the difference is ≥1 μs, the state returns to holdover to collect a second data set. When two consecutive slopes are in range, the SA.22c’s 1PPS output is synchronized to its 1PPS input.

  • Page 45: Discipline

    If at any time a 1PPS input signal is more than 330 ns from its expected value, the 1PPS algorithm returns to holdover state. If the input source is stable, the SA.22c further refines the input estimate to provide a smoother frequency output. Every minute the SA.22c saves the DDS setting in case holdover occurs.
  • Page 46 Microsemi. It is the Buyer's responsibility to independently determine suitability of any products and to test and verify the same. The information provided by Microsemi hereunder is provided "as is, where is" and with all faults, and the entire risk associated with such information is entirely with the Buyer.

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