MCE hardware
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Revision as of 09:53, 10 July 2008 by 137.82.139.157 (talk)
MCEv2 5-MDM Instrument Backplane design notes
- Jumpers
- Jumpers for signal pairs have reference designators of JPn and JNn (eg. JP1 and JN1 are signal pair jumpers)
- These jumpers are called out on the BOM as zero ohm resistors or DNP (do not populate) parts
- Zero ohm resistors will not be used for connect ground planes, copper traces will be used
- MDM routing of low-noise bias lines
How to divide up the Low Noise Bias Signals between the new Bias Cards.
- We need to maintain compatibility with existing Bias Cards which should ground these new backplane signal lines.
- Maximizing the number of Low Noise Bias Signals we could get 10 on each of BC1-BC3 for a total of 30.
- How we route them to the MDM connectors is limited but we have a few options, what seems to be best to me is
- P2 gets LN_BIAS_00 to 08
- P3 gets LN_BIAS_09 to 15 (P3 also has DET_BIAS_ORG and PXL_HTR)
- P4 gets LN_BIAS_16 to 23 with 1 spare signal (pair)
- P5 gets LN_BIAS_24 to 29 with 3 spare signal (pair)
- Mechanical - Cosmetic Changes
- Include provisions for clamping Hirose connectors
- Reorder Resistor Reference Designators so they are in order on the PCB
- Design Concerns
- A considerable number of signal lines now have 0805 zero ohm jumpers which may be difficult to layout in the space available
