• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 18 subscribers
  • Views 419 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.

SN74LVC4245A: SN74LVC4245A Ground

Stone Zeng
Prodigy 490 points
Part Number: SN74LVC4245A
Other Parts Discussed in Thread: SN74LVC8T245

This is a special application of SN74LVC4245A , GNDA is the ground of output signal which is 1V above  input signal ground(GNDB). customer perform test and found PIN11&12 and PIN13 are disconnected,  so  they separate the PORTA GND(PIN11,12) and PORTB GND(PIN13), showed as below chart, now the circuits works well.  Still has two question need your help here:

 

  1. Is  PIN11&PIN12 independent to P13 inside chip? Is ok to put 1V on PIN12&PIN and 0V on PIN13?

  2. If the answer of above question is yes, what is  minimum voltage of VCCA,?


  • 0
    TI__Guru 56100 points

    Hi Stone,

    These GND are internally connected and must not be pulled to a different level.

    As you have mentioned, Pins 11 ,12 and pin 13 are not to be considered as GNDA ,and GNDB respectively.

    The datasheet would have called out if this was the case. This level shifter cannot perform digital isolation with different gnd planes. All 3 must be connected to 0V and not to different voltages. You could also consider using SN74LVC8T245 which is P2P and allows flexible Vcc supplies ( 1.65 to 5.5V on both).