TXB porpagation delay

Hi,Niels,

The tpd variation will depend on VCCA range, VCCB range and process variation in different corner. Thus, the tpd range is from 0.4ns to 11.7ns.

Best Regards

Wei

Wei,

I have to contradict.
The TXB0104 data sheet for example lists a tpd range of 0.4ns to 11.7ns for VCCA=1.5V and VCCB=3.3V. (see picture below)

Thus, only process variation is left over as the single reason for the tpd range? Uncertainy of 2900% due to process variation? This is not what I am accustomed by TI.

I am looknig forward to your answer.

Regards,
Niels

Hi Niels

The power voltage should be considered. Thus, VCCA could be from 1.4V to 1.6V and VCCB could be from 3V to 3.6V.

Tpd variation will be smaller if VCCA=1.5 and VCCB=3.3v.

Thanks

Wei

Hello Wei,
but the TXB0104 data sheet states this delay variation for this exact configuration: VCCA=1.5V and VCCB=3.3V.
Please have a look at the second table on page 7 of the TXB0104 data sheet:

How does this fit with your statement that the Tpd vatiation will be smaller?

Regards,
Niels

Hi,

As decribed in datasheet, VCCA is 1.5V. But there is range when parameter is tested at VCCA=1.5. The VCCA range is from 1.4 to 1.6. Thus, Tpd will be tested at  VCCA = 1.4--1.6 and VCCB=3V--3.6V.

Thanks

Wei

Hello Wei,

there are a lot of ranges:

• VCCA = 1.4V to 1.6V
• VCCB = 3V to 3.6V
• T_A = -40°C to +85°C
• input rise time
• process variations during production

Do you have any information about the relationship between any of the ranges and Tpd variation?

How does a VCCA shift from 1.4V to 1.6V influence the propagation delay?
How does a VCCB shift from 3.0V to 3.6V influence the propagation delay?
How does T_A influence the propagation delay?
How does the input rise time influence the propagation delay?

Regards,
Niels

Hi Niels

The VCCA is main range. the VCCA is lower, the propagaion delay is greater? If you want to get exact vlaue, could you post the exact application condition?

I will ask help from design team to give feedback.

Thanks

Wei

Hello Wei,

sorry for the delay, we had a long weekend here in Germany.

My application conditions will be

• VCCA = 1.5V (+/-1%)
• VCCB = 3.3V (+/-1%)
• TA = -20°C to +70°C

I want to level shift the signals between a SPI-Flash and a FPGA.

Do you need any other information?

Regards,
Niels

Wei,

I hope you are well, and your silence is only caused by my complex question.

I keep the hope for getting an answer.

Regards,
Niels

Hello?

Anybody out there?

I still hope getting an answer to my  question.

Niels

Hi Niels

I would like to pitch in as this has been pending. Thank you for your patience.

Please send an email to jennifer-joseph@ti.com. I can share the data that I extracted for your specific application. I specifically looked at B to A direction as you have highlighted it.

Thanks