Part Number: SN74LVC2T45-Q1
I have updated the design, Please find it in the attached file.
Total 2 Digital input with 12V inputs and One Digital output with 5V output level.
1. Whether the design is sufficient?
2. 12V supply is Isolated but the 5V supply is Isolated as shown in the circuit, and shorted the Isolated and External GND(12V supply GND) together, will this work?
3. Or 12V also should be isolated?
Kindly support on priority.
Please note our MCU accepts only 1.8V logic level.
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.
[Same answer in the isolators forum.]
The R34/R35 voltage divider does not generate a valid logic level. To set the B→A direction, drop R34; but you can connect DIR directly to GND.
Unidirectional downtranslation can be done with a buffer with overvoltage-tolerant inputs; you can replace U21 with a SN74LVC2G17-Q1.
CMOS inputs must not float; ground pins C and D of U22.
These three level shifters do not support isolated power supplies and require a common ground on both sides. And when you do connect all the grounds together, isolating the power supplies is pointless. If you do require isolation, then you must also isolate the three signals with a real isolator like the ISO7731-Q1. (It cannot go below 2.5 V or above 5 V, so you still need the level shifters.)
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.