• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 16 subscribers
  • Views 314 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.

TMUX7348F: Missing specification on flag-pins

Josef Warta
Expert 4230 points
Part Number: TMUX7348F

Hello Team, my customer is missing some specification in the datasheet:

->  specification of the minimum current into error-flags FF and SF for HIGH state (means IOH).

There is a specification in datasheet page 8 with 5mA @ 0.35V (VOL-flag) but customer wants to reduce it to 1mA.

Idea is to use a low current LED with 1mA and 10kOhm pull-up for optical feedback and stable logic level. 

MUX will be used in a test equipment hence the LED for signaling.

In the app note there is a 1kOhm pull-up resistor used but this would not fit to the specified 5mA. Any comments on this?

In chapter 8.10 and 8.11 there is a measurement for flag timing but missing value for RPU and CL_xF.

Many Thanks

Josef

  • 0
    TI__Expert 3515 points

    Hi Josef,

    The absolute min and max that the FF and SF pins can tolerate are -10mA to 10mA:

    For VOL(Flag), IO = 5mA is the test condition for the device. A current source pulling 5mA is placed on the pin and it can still maintain the 0.35V output voltage. FF and SF pins are open drain outputs so the current is determined by the pullup resistor size and the voltage it is being pulled up too (1.8V to 5.5V for this device).

    The 1kOhm is recommended to because it will keep the tresponse(flag) and trecovery(flag) values close to the typical on the datasheet. The datasheet uses 1kOhm for RPU and 12pF for CL_xF in the test conditions column for timing specs. 

    Thanks,
    Tyler