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Tool/software:
We are observing one strange issue we are using the IC TCA9617B in LVLE3 power supply board which is already in production, this works fine with existing Spyder board. We are in development of new Spyder board we have the processor board which has Intel Arria 10 FPGA which is generating I2C data and clock at 1.8V level, I am using TCA9617B on general purpose PCB with 1.8V on A side of the IC and 5V on the B side and connected to LVLE3 Power supply which is already proven LVLE3 has same IC converting from 5V to 3.3V and connected to MSP432E411Y MCU. Issue we are observing with this setup is we are not able to get the acknowledgement from slave (LVLE3) when we send the correct I2C address from Arria 10 FPGA.
Just to isolate the issue we tried to send the same I2C packet from Arduino board, connecting Arduino board directly to LVLE3 things work fine but when we put the level translator TCA9617B soldered on general purpose PCB in between just doing level translation from 5V to 5V, we don’t see acknowledgment bit (LVLE3 pulling the 9th ack bit down). Can you please help to connect with the right technical person or group to resolve the same.
Please show the schematic, including all pull-up resistors and all I²C level shifters.
The B sides of multiple TCA9617B devices must not be connected together.
Try replacing one of the level shifters with the TCA9509; it has the restricted I/O ports on the A side.
Hi Channabasappa,
Clemens is correct here, and is further documented in this app note:
Resolving Improper Implementation of the Static Voltage Offset on I2C Buffers
Regards,
Jack
Hello can I use the IC 9509 first and then use TCA9617B. So, TCA9509 connected to Arria 10 FPGA will translate from 1.8V to 5V and 9617B connected to MSP432E411Y does the level translation from 5V to 3.3V. second half of the circuit TCA9617B & MSP432E411Y, I will not be able to change since it is part of board which is already in production and in field. I can change on the I2C master side which is having Intel Arria 10 FPGA.
Hi Channabasappa,
If it is B-side of the TCA9617B facing the B-side of the TCA9509, this will work (see figure 2-3 from app note mentioned above). Note that this is to satisfy the requirement of VCCA ≤ VCCB of the TCA9617B.
Regards,
Jack