• Table of contents
• osmo-clock-conv
  • LEDs
    • LED1 - bottom
    • LED2 - top
  • Jumpers
    • JP6 - VDD selection
    • FILTA, FILTB
    • D1, SD2
    • JP7 - single-ended vs. differential input
  • Connectors
    • K1 - External 5V DC input
    • JP5 - Internal 5V DC input
    • X5/X1
    • X6/X2
    • X7/X3
    • X8/X4
  • Schematics
  • PCB layout
  • Design Files
  • Availability
  • License

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.

LEDs¶

LED1 - bottom¶

indicator vor V+ supply voltage rail

LED2 - top¶

indicator for VDD voltage rail

Jumpers¶

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)

FILTA, FILTB¶

Please see the LTC6957 data sheet

D1, SD2¶

Please see the LTC6957 data sheet

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.

Connectors¶

K1 - External 5V DC input¶

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

Use only either K1 or JP5!

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!

X5/X1¶

• if you use differential input (JP7 open): non-inverting clock input
• if you use single-ended input (JP7 closed): clock input

X6/X2¶

• if you use differential input (JP7 open): inverting clock input
• if you use single-ended input (JP7 closed): unused

X7/X3¶

Clock output "OUT1", AC-coupled

X8/X4¶

Clock output "OUT2", AC-coupled

Schematics¶

PCB layout¶

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

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

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.

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.