Microsemi SA.22c Manuale utente
Designer Reference and User Guide
SA.22c Rubidium Oscillator
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D
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 ................................................................................................. 8
3.1 Mechanical Considerations ................................................................................................................ 8
3.2 Environmental Considerations ........................................................................................................... 8
3.2.1 Thermal Tape .......................................................................................................................................... 8
3.2.2 Water Condensation and Excessive Humidity ......................................................................................... 9
3.2.3 Excessive Dust ......................................................................................................................................... 9
3.3 External Interfaces and Grounding ..................................................................................................... 9
3.4 Electrical Interface .............................................................................................................................. 9
3.4.1 1PPS Input and Output ............................................................................................................................ 9
3.4.2 Lock Signal ............................................................................................................................................... 9
3.4.3 Service Signal ........................................................................................................................................... 9
3.4.4 Frequency Control Signal ...................................................................................................................... 10
3.4.5 ACMOS Output Frequency .................................................................................................................... 10
3.4.6 Analog Frequency Control ..................................................................................................................... 10
3.5 Modifiable Unit Settings ................................................................................................................... 10
3.6 Susceptibility to Input Noise ............................................................................................................. 10
3.7 Reliability and Maintenance ............................................................................................................. 11
3.7.1 Reliability ............................................................................................................................................... 11
3.7.2 Maintenance ......................................................................................................................................... 11
4 Installation and Operation ........................................................................................................... 12
4.1 Installation ........................................................................................................................................ 12
4.1.1 Site Selection ......................................................................................................................................... 12
4.1.2 Turn-On Procedure ................................................................................................................................ 12
4.2 Start-Up Sequence ............................................................................................................................ 13
4.3 Theory of Operation ......................................................................................................................... 14
4.4 Troubleshooting ............................................................................................................................... 14
4.5 Repairs and Support ......................................................................................................................... 14
4.5.1 Email ...................................................................................................................................................... 15
4.5.2 Contact .................................................................................................................................................. 15
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D
5 Appendix: Using the Developer’s Kit ........................................................................................... 16
5.1 Mounting the Unit with the Adapter Test Board ............................................................................. 16
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 Run Mode Data Format (Customer Mode) ........................................................................................... 25
6.1.3 Factory Mode ........................................................................................................................................ 28
6.1.4 Serial Interface Initialization .................................................................................................................. 28
7 Appendix: One Pulse Per Second Source Connection .................................................................. 30
7.1 Connection Requirements ................................................................................................................ 30
7.2 Background ....................................................................................................................................... 30
7.3 1PPS Functions ................................................................................................................................. 30
7.4 System Requirements ....................................................................................................................... 31
7.5 1PPS Algorithm Operation ................................................................................................................ 32
7.5.1 Factory Default ...................................................................................................................................... 32
7.6 Setting the 1PPS Synchronization ..................................................................................................... 32
7.6.1 Changing the y Coefficients ................................................................................................................... 33
7.6.2 The y Coefficients – Factory Default ..................................................................................................... 33
7.6.3 The j Command ..................................................................................................................................... 33
7.6.4 The g Command .................................................................................................................................... 34
7.7 Flywheeling Recovery Example–Normal .......................................................................................... 35
7.8 Recovery with JamSynch .................................................................................................................. 36
7.9 1PPS Algorithm Theory of Operation ............................................................................................... 36
7.9.1 1PPS Algorithm High Level Flow Chart .................................................................................................. 37
7.9.2 Initialization ........................................................................................................................................... 38
7.9.3 Holdover ................................................................................................................................................ 39
7.9.4 Calcslope ............................................................................................................................................... 40
7.9.5 JamSynch ............................................................................................................................................... 41
7.9.6 Discipline ............................................................................................................................................... 42
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D 1
1 Revision History
The revision history describes the changes that were implemented in the document. The changes are
listed by revision, starting with the most current publication.
1.1 Revision D
Revision D was published in November 2018. In revision D of this document, the Control Register table
was updated. For more information, see .SA-22c (and x72) Output Control Register (see page 27)
1.2 Revision C
Revision C was published in February 2018. In revision C of this document, the power sequencing was
updated to +5 V on first.
1.3 Revision B
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.
1.4 Revision A
Revision A was the first publication of this document.
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D 2
2 Overview
This section describes the SA.22c and lists its typical applications. It provides information on dimensions,
performance, and connector pinouts.
The SA.22c is a small form factor, lamp-based Rubidium (Rb) oscillator, as shown in the following figure.
This fifth-generation Rb oscillator reflects significant advances in physics miniaturization and integration.
Figure 1 • SA.22c Rubidium Oscillator
The SA.22c design is refined for low-cost mass production and can be integrated into time, frequency,
and synchronization systems. It can be directly mounted on a circuit board as a component of a module.
2.1 Applications
The wide operating temperature range of the SA.22c sets a new high-point for this type of atomic
reference. Compared with traditional quartz oscillators, the stability of the SA.22c allows it to maintain
excellent frequency control, even when the base plate temperature goes above 75 °C. When the host
system overheats in fault mode, the 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).
The design is successfully applied as an OEM component in wireless telecom networks such as digital
cellular/PCS base stations and SONET/ SDH digital network timing. When linked with a GPS receiver or
other external timing reference, the SA.22c provides the necessary timing requirements for CDMA
cellular and PCS systems. The low temperature coefficient and frequency stability extends the holdover
performance when the GPS signal is lost. Temperature compensated units are available for those special
applications that require better temperature performance.
The SA.22c produces a stable frequency with good short and long term stability and phase noise
performance.
The microprocessor-based SA.22c allows serial command selection and enables TTL-level digital output
frequencies that divide the oscillator output to a number of different frequencies compared to a single
fixed output frequency of older oscillators. The ACMOS output frequency is selected at the time of
order.
A 1PPS output is an integral part of the design. An optional 1PPS input allows the unit to track GPS or
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D 3
A 1PPS output is an integral part of the design. An optional 1PPS input allows the unit to track GPS or
other external reference. For more information, refer to 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. For more control over the device, an extensive
command control status dialog needs to be used.
In addition to controlling the operation of the oscillator, the microprocessor's built-in firmware allows
an external host computer to communicate with the embedded controller through a serial port
connection. This allows precise frequency control, dynamic frequency selection, enabling and disabling
outputs, querying the system's health, initiating a self test, and acquiring information about the unit's
serial number, operating temperature, fault history, and other performance indicators. The protocol
used is Microsemi Serial Interface Protocol (MSIP).
The following block diagram shows the importance of the digital control in the unit, how it controls and
monitors all aspects of operation, such as the heater circuits of the physics package, as well as the
selection of outputs.
Figure 2 • SA.22c Rubidium Oscillator Simplified Block Diagram
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D 4
2.2 Specifications
The following figure provides the detailed mechanical specifications of SA.22c.
Note: Datasheet specifications take precedence over this document.
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.
The following table provides information on the pin assignment and the function chart for SA.22c.
Table 1 • SA.22c Pin Assignment and Function Chart
Pin Signal Type Function
1 VSS GND Power and signal return ground (all ground pins must be connected)
2 VDD PWR 15 Vdc power input (all power pins must be connected)
3 VSS GND Power and signal return ground (all ground pins must be connected)
4 VDD PWR 15 Vdc power input (all power pins must be connected)
5 FREQ CTRL Analog Frequency control. Analog input between 0-5 Vdc
6 VCC PWR 5 Vdc power input
7 1PPS OUT Output 1PPS output, may be enabled/disabled digitally
8 VSS GND Power and signal return ground (all ground pins must be connected)
9 FACMOS Output (FACMOS) ACMOS output (frequency selectable at factory)
10 VSS GND Power and signal return ground (all ground pins must be connected)
11 VSS GND Power and signal return ground (all ground pins must be connected)
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D 5
Pin Signal Type Function
12 SERVICE Output Indicates unit is nearing limits of frequency control and that service is
required within months.
13 DIN Input UART data in at ACMOS logic levels
14 Lock Output If low, indicates Rb oscillator is locked
15 1PPS IN Input 1PPS input, positive edge triggered
16 DOUT Output UART data out at ACMOS logic levels
17 Not available
18 Not available
Note: For more information on connector manufacturer's drawings and specifications, see 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
Symbol Characteristic and Condition Value Unit
VDD Supply relative to ground 15 Vdc Input ±5 %
VCC Supply relative to ground 5 Vdc Input ±5 %
VIN Input voltage relative to
ground regardless of power
supply voltage
DIN and 1PPS IN –0.25 to 5.25 V
FREQ
CTRL
Analog external control Frequency control –0.25 to 5.25 V
PWU Maximum warm-up power <18.5 Watts
PQMaximum quiescent power At –10 °C base plate 9.3 Watts
At 25 °C base plate 7.2 Watts
At 75 °C base plate 4.6 Watts
TWU Maximum warm-up time Lock time to <1 × 10 at 25 °C
–9 <7.5 Mins
TSTG Maximum storage temperature –55 to 85 °C
Vibration (operating) GR-63-CORE, Issue 4, April 2012, section 4.4.4 and
5.4.2 Opt2: Random Vibration 0.15 grms, unit locked
Maximum altitude (powered
unit)
With respect to sea level 30,000 Feet
Maximum altitude
(unpowered)
With respect to sea level 50,000 Feet
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D 6
1.
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 Maximum Unit
Digital Inputs/Outputs
VDD Supply relative to ground 15 Vdc Input 14.75 15 15.25 V
VCC Supply relative to ground 5 Vdc Input 4.75 5 5.25 V
VIH High level input voltage DIN 2.5 5 5.25 V
1PPS IN 1.8 5 5.25 V
VIL Low level input voltage DIN 0 0.8 V
1PPSIN 0 0.8 V
VOH High level input voltage DOUT, SERVICE,
Lock at
IOH = –0.33 mA
at IOH = 0 mA
3.5 5 5.25 V
FACMOS,1PPS
OUT at
IOH = –3.5 mA
3.5 5 5.25 V
VOL Low level input voltage DOUT, SERVICE,
Lock at IOL = 0.1 mA
0 0.4 V
FACMOS, 1PPS
OUT at IOL = 1.7 mA
0 0.4 V
Analog Inputs/Outputs
VFC Frequency control input
voltage range
Resolution of
2.0 × 10–12
ΔHz/Hz
0 2.5 5 V
FACMOS ACMOS frequency output 10 MHz1–5 × 10–11 +5 × 10–11 ΔHz
/Hz
Frequency Control
ΔF/FRControl range Analog (FREQ CTRL pin)
(wide range option)
–1.5 × 10–9
–6.5 × 10–9
+1.5 × 10–9
+6.5 × 10–9
ΔHz
/Hz
Digital Interface –1.0 × 10–6 +1.0 × 10–6 ΔHz
/Hz
ΔF/FRES Frequency control resolution Digital 2 × 10–12 ΔHz
/Hz
Contact the manufacturer for information about other frequencies.
SA.22c Rubidium Oscillator
Designer Reference and User Guide Revision D 7
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.
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