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ADS42JB69: CHA 8 point sine wave pattern does not match data sheet

Charles Roberts
Prodigy 30 points
Part Number: ADS42JB69

All,

I am interfacing to a ADS42JB69 to Xilinx MPSoC. I'm using the Xilinx JESD204B core. The cards are Vadatech FMC213 and Vadatech AMC560. 

When I place the ADC into the 8 point sine wave test pattern I get a repeating pattern of -32767, -23170, 0, 23170, 32767, 23170, 0, -23170. 

The data sheet states the test pattern to be 1, 9598, 32768, 55938, 65535, 55938, 32768, 9598.

Any suggestions of where to look first to troubleshoot this?

  • 0
    TI__Guru* 91947 points

    Charles,

    Ideally no test-pattern should come in 2s complement format. Like all 1s and all 0s, the test patterns should be in straight binary format.

    But in ADS42JBxx, the 8-point sinewave pattern doesn’t form sine wave if you simply convert the captured data into decimal.

    You would need to take 2s complement (ie invert MSB) of the captured data, then convert into decimal to see a sine wave.

    Regards,

    Jim

  • 0 in reply to jim s
    Prodigy 30 points

    I se what you are saying, I converted it to binary and it makes sense now. Thanks for your help.