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TXB0104-Q1: VCCA > VCCB

Tomoaki Yoshida91
Genius 5255 points
Part Number: TXB0104-Q1

Hi Team,

We will use that both VCCA and VCCB are 3.3V, but they are supplied by another power supply IC.

In some cases, VCCA may be higher than VCCB.

Since we assume 3.3V±0.3 V for both VCCA and VCCB, VCCA is 3.6V and VCCB is 3.0 V in the worst case.

"6.15 Switching Characteristics: VCCA = 3.3 V ± 0.3 V" in the data sheet, it is specified at VCCB = 3.3 V ± 0.3 V, so we think that our usage is within specification.

Is it correct?

Please tell me if there is a risk of using VCCA at higher than VCCB.

Best regards,

Tomoaki Yoshida

  • 0
    TI__Guru* 97046 points
    Hello Yoshida-san,
    I will ask our translation expert to take a look at this post when we return to work tomorrow morning.
  • 0
    TI__Guru 62240 points
    Hi Tomoaki san,

    Please go through the app note regarding the biasing requirements for TXB .
    www.ti.com/.../scea060.pdf

    This according to me should be ok, however, as per the datasheet recommended conditions is not allowed. There could be current flowing into the Vcca pin through the Vccb pin via the clamp diodes at 0.3V delta between the supply.
  • 0 in reply to ShreyasRao
    Genius 5255 points
    Hi Shreyas-san,

    Thank you for your support.
    We assume that VCCA is 3.6V and VCCB is 3.0V In the worst case, , so it is 0.6V delta.
    I think that an increase in leakage current is acceptable, but I feel that there is risk of damage to the device.
    For example, if the delta can be suppressed to 0.3V or less, can it be said that there is no risk of damage to the device?
    I think that we can reduce the delta, but it can not make it zero.

    Best regards,
    Tomoaki Yoshida
  • 0 in reply to Tomoaki Yoshida91
    TI__Guru 62240 points
    Hi Tomoaki san,

    0.3V should be ok to not damage the device, however, 0.6V is not recommended. The fwd diode is fully biased at this point and can potentially damage device or affect the reliability in the long term.
    would you consider using DIR controlled translation?