Hi Team,
I have 2 questions listed below, please kindly help on that, thanks.
1. What's the schematic structure difference between LSF0108 and TXS0108? LSF0108 don't have one-shot circuit？
2. If the application is 50M SPI bi-direction signal, which one will be better suited?
3. Why the TPHL/TPLH time in TXS0108 is about 6ns and in LSF0108 only 1ns?
Hey Lilian,
The answers to your questions are as follows:
Lilian Chang said:
Yes, this is partially correct. The TXS series of parts has a one-shot circuit for edge rate acceleration while the LSF series of parts doesn't. More importantly, it's the reason why the TXS has that one-shot circuit; it drives FETs that drive to the Vccx rails. This is an important characteristic because the TXS series of parts has current drive built into it. The LSF series of parts are totally passive with no drive capabillity, the loads that they can drive are totally dependent on the external biasing attached. More information can be found at these hyperlinks for the TXS and LSF parts if you're interested.
Lilian Chang said:2. If the application is 50M SPI bi-direction signal, which one will be better suited?
I would recommend the TXB0108 actually, explanation in image below. LSF and TXS should also work if you'd like to use them for some particular reason but the TXB is my go to.
Lilian Chang said:3. Why the TPHL/TPLH time in TXS0108 is about 6ns and in LSF0108 only 1ns?
It has do with the passive architecture of the LSF and the TXS may have been driving higher capacitive loads since that is one thing it excels at over the others here. Possibly a reason to with it.
If this answered your question please verify the solution below using the green verification button, like knowing your problem is fixed! If you have additional questions, just send them my way and I'll work to get them answered for you.
Best Regards,
Nick
