Pumpkin UM-20 User Manual

Low-cost oven-controlled crystal oscillator

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UM-20

User Manual

750 Naples Street

•

San Francisco, CA 94112

• (415) 584-6360

•

http://www.pumpkininc.com

Low-cost Oven-controlled Crystal

Oscillator (OCXO) Assembly

Specifications subject to change without notice.

last updated on Jun 16, 2017

All trademarks mentioned herein are properties of their respective companies

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Summary of Contents for Pumpkin UM-20

Page 1: Low-Cost Oven-Controlled Crystal Oscillator (Ocxo) Assembly
• (415) 584-6360 • http://www.pumpkininc.com Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly  Copyright 2013-2017 Pumpkin, Inc. All rights reserved. Specifications subject to change without notice. last updated on Jun 16, 2017 All trademarks mentioned herein are properties of their respective companies...
Page 2 User Manual TRADEMARKS The following are Pumpkin trademarks. All other names are the property of their respective owners. • Pumpkin™and the Pumpkin logo • Salvo™ and the Salvo logo • CubeSat Kit™ and the CubeSat Kit logo DISCLAIMER PUMPKIN RESERVES THE RIGHT TO MAKE ANY CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO CORRECT ERRORS AND IMPROVE RELIABILITY, FUNCTION, APPEARANCE OR DESIGN.
Page 3: Table Of Contents
Installation ........................18 Frequency Tuning ......................19 In-place Tuning.........................19 Usage ............................20 DC Voltages........................20 Loading vs. Frequency......................20 Frequency Stability ......................20 Warmup / Initial Behavior ....................21 Oscillator Outputs ......................21 Summary ..........................22 Future Work / Enhancements ....................22 Attachments..........................23 UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 4 Table 4: Applications of Rev A OCXO Modules ................15 Table 5: OCXO131-40 frequency tuning range as a function of & ........17 Table 6: OCXO module pinout to mate to SRS DS345..............19 UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 5: Changelog
User Manual CHANGELOG Rev. Date Author Comments 20170512 Initial version. Added images of modules, included initial values, added more V_TRIM 20170608 explanatory text. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 6: Purpose
Upon first power-up and without a connected GPS antenna, it was possible to identify the location of the cell tower where the unit was located; the ones Pumpkin purchased were all from Chinese cell towers. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 7: Ocxo Replacement
These frequency counters have a 1/2/5/10MHz external reference oscillator input, and a 10MHz reference output. Via eBay and other sources, Pumpkin purchased the following models in good to excellent condition: •...
Page 8 Model 3080’s frequency input; it was, however, tunable to 5MHz when there was no load on its output. Contacting MTI for a replacement revealed that each OCXO cost around $500 new, but there was a $1500 minimum order. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 9 IsoTemp OCXO131: http://gerrysweeney.com/tag/ocxo131/ ... note that he is using an OCXO100-XXX .. that is a +5V unit. There is also an OCXO191 available (probably 12V). And this has even more detail: http://gerrysweeney.com/tag/ocxo131-191/. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 10: Ocxo Design
A high-quality multi-turn trimpot • Precision resistors in the trimpot circuit These components are expanded upon in detail below. Not present / not used on the fancier OCXO36-44 and units originally equipped with them. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 11: Barrel Jack And Mmcx Connector
It has been suggested that resistors grouped in single packages provide optimal tracking and stability, better than (separate) discrete resistors. One option would be a non-divider version of Vishay’s SOT-23 MPM-series divider networks. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 12: Circuit Design
2.5V. VCO Trim Based on Gerry Sweeney’s OCXO board’s circuit design, we selected the high-precision Maxim MAX6350 5V regulator to generate a stable voltage for the trim voltage from 12V. Its tempco UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 13: Pcb Design
Model 3xxx, it’s not connected via , and test equipment is measuring the circuit’s output via A few test points are provided to measure the VCO trim voltage, the post-regulator 12V, etc. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 14: Usage
Table 3: Frequency survey of OCXO131-40 units, installed on 705-01667A PCBs Assembly Five modules were assembled by hand, using the Pumpkin PCB and five of the six OCXO131-40s that we acquired. The module with its attached harness is shown in Figure 4 and Figure 5.
Page 15: Module Applications At Pumpkin
An XL Microwave Model 3120 with a GPS DO 10MHz external reference was used for the frequency measurements; a Fluke 289 DMM was used for the measurements; an Agilent E3620A provided the V_TRIM voltage V_TRIM 12Vdc power. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 16: Use In Xl Microwave Model 3Xxx
, the trim range of the VCO (stated by IsoTemp to be up to 0.9ppm or 9Hz over the full range) required a full ±2.5V of at the VCO input with = 1kΩ. To reach a V_TRIM UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 17: In-Place Tuning
Model 3xxx be upside-down when adjusting the OCXO frequency. A carefully positioned hole could be drilled in the lower cover of the Model 3xxx, to gain access to the PCB assembly’s trimpot without removing the lower cover. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 18: Use In Srs Ds345
Option 02 (Internal OCXO). Since the Pumpkin OCXO module was not designed for use in the DS345, we had to find a robust way to mount it. We found that in the DS345’s rear corner where the various back-panel BNCs are...
Page 19: Frequency Tuning
OCXO on its connector (the factory OCXO). By U203 connecting this signal to the VCO input on the Pumpkin OCXO module, DS345 users can fine-tune the OCXO’s frequency using the DS345’s internal calibration byte #0. Since is driven OPT_VCO by an op-amp, the effect of the OCXO module’s trimpot on its...
Page 20: Usage
Once installed in the Model 3xxx, the frequency of the OCXO PCB assembly is measured at the Model 3xxx’s output BNC on its back panel. These tests were performed without any thermally encapsulating epoxy on the PCB assembly. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 21: Warmup / Initial Behavior
50Ω is shown Figure 8. Figure 8: OCXO36-44 waveform (blue) compared to Z3805A GPS-disciplined waveform (yellow) The output of the OCXO131-40 through the Model 3xxx’s 10Mhz output terminated into 50Ω is shown Figure 9. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 22: Summary
NVM. A command and telemetry interface would permit this to be automated. Interestingly, MTI now offers the 220-series OCXO in standard, hi-rel and space versions. UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly...
Page 23: Attachments
User Manual Attachments Schematics and PCB layers of the PCB (Pumpkin P/N 705-01667A) are attached, along with datasheets associated with the various critical components utilized in or associated with the PCB and its design. Third-party datasheets are attached for reference only and do not imply any endorsements, etc.
Page 24 Comment Description Designator Quantity Supplier 1 Supplier Part Number 1 47uF 7343 47uF Tantalum Cap 1 Digi-Key 399-3905-1-ND 470nF 0805 470nF Chip Cap 1 Digi-Key 399-11174-1-ND 100nF 0805 100nF Chip Cap C3, C4, C8 3 Digi-Key 478-3352-1-ND 2.2uF 0805 2.2uF Chip Cap C5, C6 2 Digi-Key 445-8787-1-ND...
Page 25 750 Naples Street San Francisco, California 94112 Bus Interface Module - Top Sheet Title OCXO 3xxx Module Size Number Revision (C) 2001-2017 Pumpkin, Inc. 705-01667 For use in XL Microwave 3030/3080/3120/3200/3260 Frequency Counters. Letter Doc. Rev: 01 Date: 5/13/2017 Sheet of...
Page 36 OCXO Layout Guidelines Application Note: AN2093 2111 Comprehensive Drive Aurora, Illinois 60505 Section 1: About this document. Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com 1.1 Introduction The techniques included in this application note will help to ensure successful printed circuit board layout using an oven-controlled crystal oscillator (OCXO).
Page 37 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Section 2: Power & Ground Considerations. 2.1 Power Supply and Grounds. For the OCXO to power up and configure properly on initial power-up, Vcc must exceed the maximum All system designs have a power supply and power-on reset (VPOR) voltage in order for the device ground circuit that is shared by all of the components...
Page 38 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com 2.7 Brown-Out Reset. 2 8 Voltage Regulators. When the device powers down, the device Vcc A voltage regulator takes an input voltage from will cross the VPOR / VBOR voltage. Once the Vcc an external source and steps it down to a suitable voltage decreases below the VPOR / VBOR voltage voltage level that can power components on the...
Page 39 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com 2.9 Low-Dropout Regulators. 2.12 Designing with a Ground Plane. Low-Dropout Regulators (LDOs) are less efficient While some systems connect components to a than dc-dc converters, but they also introduce ground circuit through wires or traces most designs significantly less noise into the power circuits.
Page 40 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Section 3: Theory of Operation / Characterization. 3.1 OCXO Theory of operation. The OCXO encloses a crystal in a temperature-controlled chamber called an oven. Frequency stability is achieved by maintaining tight temperature control of the crystal within the oscillator oven.
Page 41 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Thermal Performance Characteristics. Test Conditions: OCXO mounted in socket, VCC=3.3V, Temperature = @25°C unless otherwise noted. The following graphs represent the typical characteristics of a DOC052F-010.0MHz OCXO. Consult with Connor-Winﬁeld Engineering Department for characterization data on any of our existing models.
Page 42 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Thermal Performance Characteristics. Figure: 7-01 Typical Warm-up Time (seconds) Figure: 7-02 Retrace after power cycle. Figure: 7-03 Typical Warm-up Time (seconds) Figure: 7-04 Typical Warm-up Retrace Curves AN2093 Application Note Page...
Page 43 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Thermal Performance Characteristics. Figure: 8-01 Typical Warm-up Retrace Curves Figure: 8-02 Typical Oscillator Output Start Time Figure: 8-03 Frequency Error vs Supply Voltage Figure: 8-04 Typical Frequency Stability vs drift ( nom, +5,-5,nom) Temperature AN2093...
Page 44 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Thermal Performance Characteristics. Test Conditions: OCXO mounted on 0.062” 6 layer board, VCC=3.3V, Temperature = @25°C unless otherwise noted. The following graphs represent the typical characteristics of a DOC052F-010.0MHz OCXO. Consult with Connor-Winﬁeld Engineering Department for characterization data on any of our existing models Time (s) Figure: 9-01...
Page 45 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Thermal Performance Characteristics. Figure: 10-01 Typical Warm-up Time (seconds) Figure: 10-02 Retrace after power cycle. Figure: 10-03 Typical Warm-up Time (seconds) Figure: 10-04 Typical Warm-up Retrace Curves AN2093 Application Note Page...
Page 46 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Thermal Performance Characteristics. Figure: 11-01 Typical Warm-up Retrace Curves Figure: 11-02 Typical Oscillator Output Start Time Figure: 11-03 Frequency Error vs Supply Voltage Figure: 11-04 Typical Frequency Stability vs drift ( nom, +5,-5,nom) Temperature AN2093...
Page 47 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Electrical Characteristics Test Conditions: OCXO mounted on 0.062” 6 layer board, VCC=3.3V, Temperature = @25°C unless otherwise noted. The following graphs represent the typical characteristics of a DOC052F-010.0MHz OCXO. Consult with Connor-Winﬁeld Engineering Department for characterization data on any of our existing models Figure: 12-01 Typical Oscillator Output Start Time Figure: 12-02 Control Voltage Tuning Linearity...
Page 48 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Typical Electrical Characteristics Figure: 13-01 Figure: 13-02 Figure: 13-03 Figure: 13-04 AN2093 Application Note Page Revision 10 May 2013 Date Speciﬁcations subject to change without notice. All dimensions in inches. © Copyright 2012 The Connor-Winﬁeld Corporation...
Page 49 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Section 4: Multi-Layer Board Design / Thermal Considerations 4.1 Layout Considerations Always use speed rated level translators or To achieve the stated frequency stability specifications buffers in applications requiring communication the OCXO must be able to reach and sustain thermal between digital devices operating from multiple...
Page 50 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Multi-Layer Board Design / Thermal Considerations Free via size calculations tools are available online. The DAC which drives the OCXO CV pin is Saturn PCB Design Inc. offers this free tool available at powered from a secondary 3.3V rail (3v3_ the following URL.
Page 51 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Multi-Layer Board Design / Thermal Considerations Figure: 16-01 Figure: 16-03 A small air gap should exist between the OCXO and all the walls of the cover. 11.
Page 52 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Multi-Layer Board Design / Thermal Considerations Figure: 17-01 Optionally a thermal “moat” can be created to prevent thermal energy transfers between the OCXO and the surrounding heat generating components.
Page 53 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Multi-Layer Board Design / Thermal Considerations 4.3 Controlling Thermal Transfer / Transients Controlling thermal transients is critical for proper operation of all OCXOs. Any sudden changes in air-flow, or temperature will drastically effect short term frequency stability.
Page 54 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Section 5: Design Checklist 5.1 Power Supply Checklist • Select a LOW noise power circuit / source • Add a large bulk capacitor at the voltage regulator’s output that can provide current for local capacitors and ensure regulator stability.
Page 55 2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com Design Checklist 5.4 OCXO Layout Considerations • Always place OCXO as close to timing circuitry as possible.. • Always adhere to stated loading specifications for RF output of OCXO and consider using NPO / COG capacitors to create equivalent loading capacitance for optimal capacitance vs.
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