• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 32 subscribers
  • Views 121 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.

TLK1501EVM: Inquiry

Cedrick
Expert 8270 points
Part Number: TLK1501EVM
Other Parts Discussed in Thread: TLK1501

Hi,

Good day.

Our customer has a question regarding the TLK1501EVM. Kindly see below.

""I have a doubt about the use of the 10nF capacitor connected to ground between the two 50ohm termination resistors on the evaluation board of the TLK1501 (RX lines)
On the datasheet there is no capacitor between the termination resistors, and the line is described as differential terminated with 100ohm in total, while on the evaluation board there is the 10nF capacitor which seems showing the RX lines as two single ended 50ohm lines.
Could you please let me know if the 10nF capacitor is required, and what is its use?""

Looking forward to your inputs. Thank you.


Regards,

Cedrick

  • 0
    TI__Mastermind 19135 points

    There is no requirement to have capacitors going to GND on the high speed lines. Depending on the I/O logic type of the chip the TLK is interfaced to, the end user may implement AC coupling capacitors on the serial high-speed I/Os.

    Thanks,

    Rodrigo Natal

  • 0 in reply to Rodrigo Natal
    TI__Expert 8270 points

    Hi Rodrigo,

    Good day. Thank you for your response.

    Our customer has an additional clarification on this.

    ""I have a final question as consequence of the response given by your engineers:
    Is the schematic of the TLK1501 evaluation board in some way wrong because it uses the 10nF capacitor connected between the 2 termination resistors 50ohm and the GND on the rx lines?    ""

    Thank you.

    Regards,

    Cedrick

  • 0 in reply to Cedrick
    TI__Mastermind 19135 points

    Hi. There is no error at all in the TI evaluation board schematic. The TI evaluation board and datasheet schematic recommendations are consistent. For both cases, you have 50 ohm single-ended terminations reference to VDDA. The EVM then implements a 0.01uF bypass capacitor from VDDA to GND to filter high frequency noise. It's a good practice.