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AM26LV32: Difference between AM26LV32 and AM26C32

Yue TANG
Expert 8705 points
Part Number: AM26LV32
Other Parts Discussed in Thread: AM26C32,

Hi,

My customer used to use AM26C32 and AM26LS31CDR. but recently, they changed the AM26C32 to AM26LV32 . and found AM26LV32 has a higher rising time comparing to AM26C32.  would you please suggest what's difference between these two and possible reason to the rising time.  picture as below:

AM26C32: b-a =6ns

AM26LV32: b-a =12ns

 

 

  • 0
    TI__Mastermind 25705 points
    Yue,

    Please notice AM26C32 is a 5V device and AM26LV32 is a 3V device. Please make sure your customer apply the correct supply. Also because the devices work with different supply voltage, AM26C32 receiver's output buffer is has a little stronger than AM26LV32's. Please let me know if this would create any issues in application.

    Regards,
    Hao
  • 0 in reply to Hao L
    TI__Expert 8705 points
    Hao,
    Thanks for the reply. As I mentioned, AM26LV32 caused a higher rising time, do you know the reason why? Please also kindly feather comment what's the benefit with a stronger output buffer? Where can I find the description of this "output buffer" parameter? thanks.
  • 0 in reply to Yue TANG
    TI__Mastermind 25705 points
    Yue,

    Please confirm AM26LV32 is supplied with 3.3V and AM26C32 is with 5V in your testing. In general the lower supply leaves a lower head room for the transistors in the driver of IC, which usually means the driver shows more resistance (Rsd on). Please let me know if it makes sense to you.

    Regards,
    Hao
  • 0 in reply to Hao L
    TI__Expert 8705 points

    Hao,

    Yes. the power supply is right. please see below . please kindly help to accelerate it.  thanks.  

    The test points are show in the picture corresponding to the figure above.

    The issue is : LV32 introduce  higher delay than  C32. 

    Support need:

    1. What is the root cause? how to fix this?

    2.Are there any other difference between LV32 and C32 except the supply voltage?

    Below one, run normally 

  • 0 in reply to Yue TANG
    TI__Mastermind 25705 points
    Yue,

    Thanks for your information. The input of AM26C32 and AM26LV32 are very similar. Actually AM26C32 has higher input resistance that AM26LV32. Does your customer complain AL26LV32 has slow rise/fall time or unbalanced rise/fall time? If it's slow rise/fall time, the reason might be due to smaller input resistance, which is equivalent of adding more load to the bus. You could try smaller serial resistors and bigger pull up/down resistors. If it's unbalanced rise/fall time, you could bias pull up at 5V instead of 3.3V, since AM26LV32 can take 5V logic. Please let me know if you have more questions.

    Regards,
    Hao