• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 18 subscribers
  • Views 716 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.

SN74LVC1404: Output level too low under three couple 1000pF caps

Jeff Xie
Intellectual 1780 points
Part Number: SN74LVC1404
Other Parts Discussed in Thread: SN74AUP1T50

Hi all,

Below is the schamtic, when all three outputs are used, high level volatage  of OSCIN_24MHz  is 1.27V  , AEC_24MHZ is 1.2V，HDMI_I2S2_MCLK is 0.65V, (clock high level minimum 2.31V) . The voltage is too low. But when I  delete one output, the left two outputs are :OSCIN_24MHz -2.89V ， AEC_24MHz -3.05V ,which meet the requirement. 

1. Does this chip not support three outputs because of output current?

2. If I want to support 3 outputs, can I use a buffer like SN74AUP1T50 to buffer one output, as two outputs are OK, or do we have socket can support 3 outputs?

  • 0
    TI__Mastermind 44620 points
    Hi Jeff,

    Most likely your load is too heavy. I'd recommend feeding the OSCOUT signal into A input and connect Y to R1007. This may provide more drive strength for you. If that doesn't work let me know and we can try to come up with a different solution.