sPHENIX MAPS tracker discussion

["Schambach, Jo" <schambachjj AT ornl.gov>]

With the help of Cameron, I just tested one of the “short” Samtec cables wrt data transmission errors at 1.2Gbps. We used the telescope setup for that purpose.

I first verified that all staves of the telescope have no PRBS errors at 600Mbps with the “default” cables currently installed. This seemed to be OK.

I then programmed the RUs with the firmware that uses 1.2Gbps for the data transmission from the staves. With the default cables I saw PRBS errors at that speed in RUs 0, 9, 15, 18, and 21 (i.e. 5 out of 8 RUs), with the worst being 21 and 9.

Cameron then installed one of the shorter cables, but the first cable used had at least 2 of the 9 chips not lock to the transceiver on the RU.

A second cable worked OK with the transceiver lock, however, there were immediate PRBS errors on all of the chips. I tried increasing the operating voltage to 1.9V (from 1.8V), but got the same result. Increasing the driver current to its max also didn’t make a difference.

 

So this is not looking too good for the prospect of using higher speed readout from the staves….

 

Jo

 

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Joachim Schambach

Oak Ridge National Laboratory

PO Box 2008

Bldg. 6000, MS 6368, Rm 205-C

Oak Ridge, TN 37831-6368

Phone: (865) 341-0694

Email: schambachjj AT ornl.gov