For New Space applications AXTAL offers as special service the sourcing and/or up-screening of commercial quartz crystal units with proven quality level to so-called “Space-COTS Crystals” (SCC) increasing the range of available package styles
Sourcing can be
- From “CROVEN CRYSTALS“ in Canada (the one who supplies the crystals used in the EPPL listed AXTAL OCXO AXIOM6060) with long Space heritage
- From a manufacturer with automotive certification (ISO16959)
- From a manufacturer with aerospace certification (ISO/AS9100)
- From a manufacturer with heritage for crystals for MIL applications, and with established statistical process control (SPC) and traceability
Up-Screening can be performed at different levels:
- Screening according to MIL-PRF-3098 Level “S” or Level “B”
- Screening to a relaxed level “X”, introduced and used by AXTAL for several space customers, see the following table
Screening (MIL-PRF3098K)
| Test Inspection | Level S | Level B | Level X* |
|---|---|---|---|
| Pre-seal visual examination | 4.10.2.2 | 4.10.2.2 | 4.10.2.2 |
| PIND | 4.10.16 | N/A | N/A |
| Thermal frequency repeatability | 4.10.15, 10 cycles | N/A | N/A |
| Frequency and resistance | 4.10.6 (@ Tief) | 4.10.18 | 4.10.6 (@ Tief) |
| Unwanted Modes | 4.9.10 | N/A | 4.9.10 |
| Shunt capacitance | 4.10.7.1 | N/A | 4.10.7.1 |
| Motional capacitance | 4.10.7.2 | N/A | 4.10.7.2 |
| Quality factor | 4.10.8 | N/A | 4.10.8 |
| Aging | 4.10.27, 3, 30 days@85ºC, |Af/f| | N/A | N/A |
| Drive sensitivity (DLD) | 4.10.11 |Af/f| | N/A | 4.10.11 |Af/f| |
| Vibration | 4.10.14 |Af/f| | N/A | 4.10.14 |Af/f| |
| Thermal shock | 4.10.19.2, |Af/f| | N/A | 4.10.19.2, |Af/f| |
| Insulation resistance | 4.10.10 | N/A | 4.10.10 |
| Coupled modes (frequency dips) | 4.10.6.2 | N/A | 4.10.6.2 |
| Frequency and resistance | 4.10.6 | N/A | 4.10.6 |
| Frequency and resistance vs temperature | 4.10.6.1 | N/A | 4.10.6.1 |
| Seal | 4.10.26 | 4.10.26 | 4.10.26 |
| Radiographic inspection (when specified) | MSFC-STD-355 Apdx. M | N/A | N/A |
| Visual (extrenal) and mechanical inspection | 4.10.2.1 | 4.10.2.1 | 4.10.2.1 |
*AXTAL procedure
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