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alice-fit-fee-upgrade / FIT_lab_40MHz_clock_source

small, portable 40MHz clock source with LVDS and SFP output
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clock source #1

Open gkasprow opened 7 months ago

gkasprow commented 7 months ago

It's a portable LHC clock source (40,0787MHz). Initial specification:

The signal is generated using 2x faster oscillator from Microsemi then divided /2 by lvpecl flip flop and distributed using lvpecl buffer to:

The board will be in 100x160mm form factor. Supplied from usb-c connector and 4 pin12V molex connector used in Sinara HW

The card can be installed in 3U crate or in a stand-alone Hammond box. Such approach is used in Thermostat design.

micbeldyga commented 5 months ago

Let's get the ball rolling! Few questions so far:

  1. Do we already have specific components selected? (oscillator, clock dividers/multipliers)? If so, have the component symbols been commissioned?
  2. Should "SMA output via capacitor" be implemented as AC coupled LVPECL output routed as 2x50Ω SE?
  3. Should either 5V or 12V have a priority or would simple diode oring suffice?
  4. Any particular requirements for front panel layout?
  5. Not really a question - seems like 1455L1601 from Hammond is what we should aim for.
gkasprow commented 5 months ago
  1. OSC_80.1574MHZ_MICROCHIP_DSC1123DI2 from CERN lib; rest can be selected from CERN lib or other source
  2. yes
  3. diode oring is fine, we will supply logics from 3.3V anyway so LDO would be needed. Just add low cost dc/dc with integrated inductor.
  4. your choice, post initial placement here before layout
  5. ACK