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TXS0101 Partial Powerup

Don Schelle
Expert 4150 points
Other Parts Discussed in Thread: TXS0101

Hello,

I'm using the TXS0101 in a level translation application configured as such:

VCCA = 1.8V

VCCB = 2.5V

OE = Connected to VCCA via a 10K pullup resistor

There is the possibility of VCCA being powered while VCCB is at 0V for prolonged periods of time.

Some questions:

1. The datasheet suggests that during powerup, VCCA can be greater than VCCB.   Is there a time restriction on this requirement?

2. The datasheet also suggests that OE must remain low until VCCA and VCCB fully ramp.   This is not the case in our circuit.   Will this cause damage to the device?

3. When operating in this condition, are there any negative side effeects if the I/O on VCCB is driven to 2.5V, without applying VCCB?

Don

  • 0
    TI__Mastermind 29985 points
    Hello Don,

    1. There is no restriction on this time requirement. Either VCCA or VCCB can be higher with no issues.

    2. You can tie OE to VCCA. It will not damage the device. Tying OE to GND will ensure no glitches at the IO ports during power up. If this is not important for your design then OE can be permanently pulled high.

    3. You should not apply inputs to B port IO when VCCB is low. When VCCB is low this will put the A port IO into a high impedance state, not the B port. I took some measurements in the lab (with a TXS0104, no access to a TXS0101 but the results should still be relevant) and when applying 2.5V to the B1 port with VCCB at 0V I was getting large amounts of current flowing (10s of mA) into VCCB.