Hardware Projects » osmo-clock-conv

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h1. osmo-clock-conv

The osmo-clock-conv is a small board for low-jitter conversion of a sine clock into a square clock, based around the "LTC6957-4":https://www.analog.com/en/products/ltc6957-1.html.

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h2. LEDs

h3. LED1 - bottom

indicator vor V+ supply voltage rail

h3. LED2 - top

indicator for VDD voltage rail

h2. Jumpers

h3. JP6 - VDD selection

There are three potential sources for the VDD voltage:

* *VDD uses V+ rail* (output of internal LDO): JP6 on pins 2-3

* *external VDD source*: voltage can be supplied on pin 3

* *external LDO*: can be placed between JP6 pin 1 (V_IN supply) and 3 (regulated VDD output)

h3. FILTA, FILTB

Please see the LTC6957 data sheet

h3. D1, SD2

Please see the LTC6957 data sheet

h3. JP7 - single-ended vs. differential input

If JP7 is closed, it disables the inverting clock input (IN-) of the LTC6957.  X6/X2 can no longer be used.

h2. Connectors

h3. K1 - External 5V DC input

This is the power input for an external 5V DC power supply.

*Use only either K1 or JP5!*

h3. JP5 - Internal 5V DC input

In case *osmo-clock-conv* is part of a larger assembly/device, you may already have a 5V DC supply internally.

*Use only either K1 or JP5!*

h3. X5/X1

* if you use differential input (JP7 open): non-inverting clock input

* if you use single-ended input (JP7 closed): clock input

h3. X6/X2

* if you use differential input (JP7 open): inverting clock input

* if you use single-ended input (JP7 closed): unused

h3. X7/X3

Clock output "OUT1", AC-coupled

h3. X8/X4

Clock output "OUT2", AC-coupled

h2. Schematics

!osmo-clock-conv-v1-sch.png!

h2. PCB layout

The PCB design is a dual-layer board in 100x50mm size.  All connectors are exposed on one edge.

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h2. Design Files

The design files can be found in the @osmo-small-hardware.git@ repository. Web access is provided via https://gitea.osmocom.org/electronics/osmo-small-hardware/src/branch/master/clock-converter

h2. Availability

This project is currently in the design verification stage. Once the verification has completed, it is expected that osmo-clock-conv boards will be made available via the "sysmocom webshop":https://shop.sysmocom.de/.

h2. License

The osmo-clock-conv design is made available as Open Source Hardware (OSHW) licensed under CC-BY-SA (Creative Commons Attribution Share-Alike).

This means anyone can use the design to build units, or to create derivative versions of the design. However, you have to give attribution and release your derivative works under the same license as the original project.