LM97600RB: ByteAlign and ChanAlign are do not align on the new reference board.

Dan Ferguson

Part Number: LM97600RB
Other Parts Discussed in Thread: WAVEVISION5

Hello,

I cannot get the ByteAlign and ChanAlign values to become all 1's. I have reconfigured the PLLs, re-read the registers and performed Sync Req's but byte 4 or byte 8 always show up as 0. I have gotten all 1's once but never again. Is there a known strategy to get this to work?

I am using WaveVision5.06.465.

Thanks,

Dan Ferguson

over 7 years ago

0 dBrock over 7 years ago

TI__Genius 12780 points

Hi Dan,

We are taking a look into your question, and will be back with you soon.

Best Regards,

Dan

0 Jim Brinkhurst1 over 7 years ago in reply to dBrock

TI__Mastermind 44680 points

Hi Dan

Here is the first thing I would check. In a previous manufacturing run of this board one component was included in the assembly that shouldn't have been. R701 should not be installed.

See the attached schematic here:

/cfs-file/__key/communityserver-discussions-components-files/73/2068.LM97600RB-RevX2-Schematic-Prints.PDF

and assembly drawing here:

/cfs-file/__key/communityserver-discussions-components-files/73/6735.Assembly-Drawings-R701-Removal.pdf

If R701 is installed it shorts the differential output of the oscillator providing the reference clock to the FPGA High Speed Serial Transceiver block. I have seen where even when that output was shorted it would allow the board to succeed with the alignment process a few times.

If the resistor is there (as shown on page 2 of the assembly diagram) please remove it from the board and then try again and let me know the results.

If the resistor isn't there let me know and I'll come up with some other steps for debugging.

Best regards,

Jim B

0 Dan Ferguson over 7 years ago in reply to Jim Brinkhurst1

Prodigy 20 points

Hi Jim,

R701 is not installed on this board and I measure ~240kOhm with a DMM across the pads.

Thanks,

Dan

0 Jim Brinkhurst1 over 7 years ago in reply to Dan Ferguson

TI__Mastermind 44680 points

Hi Dan
It might be worthwhile trying external clocking mode to see if the issue is with the on-board PLL.
To use external clocking you need to apply 2 clocks.
The ADC_CLK signal (+2dBm) will be a frequency in the range of 1 to 2.5 GHz. The REF_CLK input must be exactly ADC_CLK/12.5 at a similar amplitude to the input of the provided balun board. For 2.5 GHz ADC_CLK the REF_CLK is 200 MHz. These two clock generators must be frequency locked using a common reference.
If you have these clock sources available then apply the clocks to the respective inputs and configure the EVM GUI for external clock mode at that frequency. Let me know if the results are different than when using on-board clocking.
If you don't have external clocks sources available then I recommend starting on the board return process. If the board was ordered through a distributor contact them. If it was ordered from the TI Store please contact review the information available here:
www.ti.com/.../faq-returns-and-refunds.html
In the meantime you could verify the supply voltages at the various test points. Refer to the schematic details in the LM97600RB Design Package available here:
www.ti.com/.../LM97600RB
Best regards,
Jim B

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LM97600RB: ByteAlign and ChanAlign are do not align on the new reference board.