Hello team,
I have two questions related LDC1614 EMC.
1) A steep noise peak in 400M/800MHz is observed in the customer's design. Is there any possible rout cause on the device internally? The peak level isn't depend on the sensor current but increased when using longer I2C cable.
2) Do you have any data or evidence for EMC immunity of LDC1614 device itself? (e.g. for IEC61000-6-2 standard)
Regards,
S.Sawamoto
Hi Shinya,
Thanks for reaching out. We wouldn't recommend using the I2C interface over long wires, this of course can results in EMI. You will have to consider using another interface that is meant for transferring over longer distances and is better EMI performing.The EMI results will vary depending on the sensor characteristics (coil diameter, current drive setting, etc) and the mechanics of the whole system (metal shielding, stackup, etc).
For example, we've done a test with the LDC1614 using external muxes to achieve 16 sensors, each with diameter of 16mm for a stainless steel keypad demo.
The metal is 0.6mm stainless steel separated from the sensors by a distance 0.4mm.
The EMI results are shown below:
You can see that given this system configuration we pass the CISPR 22 Radiated Emissions Class B spec with almost 20dB of margin across the whole frequency spectrum.
To get results specific to your system, we recommend to prototype the whole system, but you can have confidence that the LDC1614 family of products are a low noise solution.
You can see more recommendations of dealing with EMI in the following app note: https://www.ti.com/lit/an/snoa962/snoa962.pdf?ts=1594993415401&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLDC1614
Regards,
