TXB0108's behaviour if OE enabled before Vcc stable.

Yee Yong Teo

Expert 4335 points

Hi,

In the datasheet, it stated the below (highlighted):

What will happen if OE is enabled before both Vcc fully ramped and stable?

Thanks.

- YY

over 8 years ago

0 aozer over 8 years ago

TI__Mastermind 30545 points

Hello Yee,

You may see some glitches at the output if OE is enabled before Vcc is stable.

0 Yee Yong Teo over 8 years ago in reply to aozer

TI__Expert 4335 points

Hi Aozer,

1. What type of glitches would be expected?
2. I/O port not having Hi-Z? in low resistance?
3. Will the buffer suffer certain damage and degraded?
4. Device is partially powered down when either VCCB or VCCA is 0V. What is the threshold voltage to power down the device during VCCA/VCCB ramping down?

Thanks.

- YY

0 Yee Yong Teo over 8 years ago in reply to Yee Yong Teo

TI__Expert 4335 points

Hi Aozer,

Any update to my questions above?

Thanks.

- YY

0 aozer over 8 years ago in reply to Yee Yong Teo

TI__Mastermind 30545 points

Hello,

Sorry for the late reply.

1. You may see momentary pulse at one or more output ports during power sequencing

2. If OE is not pulled to GND we cannot guarantee the status of the I/O port during power up. It may be in Hi-Z or may not.

3. You will not damage the device.

4. We do not spec a threshold voltage for Ioff. Generally, we do not guarantee partial power down state unless the supply is at GND. If this is a problem I can try to take some measurements in the lab to find an approximate threshold voltage.

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TXB0108's behaviour if OE enabled before Vcc stable.