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  • TI Thinks Resolved

ADS54J60: Inconsistencies in datasheet, JESD mode,

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Replies: 5

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Part Number: ADS54J60

Dear TI,

please clarify the following inconsistencies from datashet of ADS54J60 (revision January 2017):

1) Table 14 suggest for LMFS = 4211 operation the JESD mode to be set to 0x4. Table 17 suggest 0x2. Which is correct / what is the difference?

2) JESD digital page (0x6900) register 0x7 read back after initial resets shows 0x9. This is contradictory to Table 56 which implies 0x4 to be default value. Which bit should be set to select subclass 1? Bit 0 or bit 3? What about the MSB?

3) General registers 3 and 4 are marked R/W in table 20/21. Yet I never succeeded in reading them (0xc003 / 0xc004).

Thank you in advance
- Jiri

  • Hi Jiri
    Regarding your questions. These answers are based on the latest version of the datasheet available at TI.com.
    1) Table 14 is correct. The setting of 0x2 is for 4244 framing mode.
    2) The default read-back of this register after power-on is 0x08h. (bit 3 is 1, all other bits are 0). This default value selects Subclass 1.
    3) I will double check with the IC designers regarding the ability to read-back these register values.
    Best regards,
    Jim B
  • In reply to Jim Brinkhurst84999:

    Hi Jim,

    thank you for the answers!. Just to note: default readback after power-up on the chips that I have, for the question 2) is not 0x8 but is 0x9, hence the origin of the question. So then what about the LSB, can it be zeroed, or must be written with 1?

    Best regards

    - Jiri

  • In reply to Jiri Kral83:

    Hi Jiri
    I checked what is written in the ADS54J60EVM GUI configuration files. In those files there is no write to Digital Page 6900h Register 7h, so you can leave that register at the power up default value of 0x9h.
    I'm not sure why the datasheet says the LSb must be written to 0. I will check with the device expert who will be back in the office in a few days. If the datasheet is in error we will incorporate this change in the next revision.
    Best regards,
    Jim B
  • In reply to Jim Brinkhurst84999:

    Hi Jiri
    I also confirmed that general registers 3 and 4 (JESD BANK PAGE SEL) are not available for read-back.
    Best regards,
    Jim B
  • In reply to Jim Brinkhurst84999:

    Thank you Jim.

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