Part Number: TXB0108
I have application where I am translating from a 3.3V device (LMK04821) to a 1.8V FPGA. The translation is on the SPI bus but I have noticed the LMK04821 only has a 500uA drive strength on the SDIO pin.
What would be the performance limitation with this drive strength?
If unworkable can you advise on a suitable translator. Maximum clock speed is 20MHz..
The TXB translator, like all auto-bidirectional translators, requires a driver that can overpower it -- with only 500uA of drive strength, the device could become 'stuck' in one state, not being able to switch.
I would recommend using the SN74AXC4T774 for 3.3V to 1.8V SPI translation. This device allows for individual direction selection on each channel and avoids all the problems associated with autobidirectional voltage translators. SPI bus typically has 3 signals in one direction and one in the other with no need for changing directions.
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
In reply to Emrys Maier:
sorry for the slow response, I have subsequently found out that the LMK4821 supports 4-wire SPI so that does make the problem easier. In the end added a buffer onto the MISO line as we are too far advanced with the design to change now however in the future I will consider different translators.
In reply to ken mason:
Thanks for letting me know. Come back any time!
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.