• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 46 subscribers
  • Views 118 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS4245: ADC digital CMOS outputs driving traces > 2"

Nicholas Schaub
Prodigy 30 points
Part Number: ADS4245
Other Parts Discussed in Thread: SN74AVC16T245

Dear Friends at TI:

I have selected the ADS4245 for use in my application. In this scenario, the CMOS outputs on the ADC will drive a board-to-board connector and several inches of PCB traces. Section 10.2.2.3 Digital Interface in the ADS4245 datasheet recommends using a CMOS buffer when driving distances greater than a few inches. This seems like one of those instances. My questions:

(1) Do I need a buffer?

(2) Can you recommend a buffer/driver and/or reference design?

(3) What risk do I assume by omitting a buffer under these circumstances?

(4) Is there any risk to timing or other implications of inserting a buffer in the path?

Thank you so much for your assistance.

Nick

  • 0
    TI__Guru* 91947 points

    Nick,

    (1) Do I need a buffer? Yes

    (2) Can you recommend a buffer/driver and/or reference design? SN74AVC16T245

    (3) What risk do I assume by omitting a buffer under these circumstances? Depending on clock speed, the data signal integrity may be degraded resulting in bad data captures.

    (4) Is there any risk to timing or other implications of inserting a buffer in the path? Make sure to send the ADC output clock through the buffer as well so that all data lines and clocks have the same added delay. You may also want to add some dampening series resistors at the output of the buffer to minimize reflections. See attached TI EVM schematic for an example.

    Regards,

    Jim

    5466.ADS42XX_58C28EVM-SCH_C.pdf