CN0359 Eval Kit Circuit Changes

Hello,

We've previously respun the CN0359 circuitry into a PCB to reduce the form factor, and we're in the process of doing it again to make it even smaller. In this respin, we're hoping to make a couple modifications to fit the form factor we need and for it to properly work in our application and want some advice.

First, is there a smaller alternative to the EMI filters (PN BNX025H01L) used in the power circuitry? Our application is powered off a battery pack, so we're also considering just removing them altogether.

Second, are there any recommendations on ICs and their integration to provide isolation between the data and power signals?

Thanks!

Parents Reply
  • Can you go into more detail about choosing the right ferrite bead? I understand the implementation described in the application note, but still am not sure how to choose the correct ferrite bead. The ADP2300 in the circuit has a switching frequency of  700kHz and the ADP1613 in the circuit has a switching frequency of 650kHz. Both seem lower than the intended frequency range of ferrite beads

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    •  Analog Employees 
    on Jun 17, 2021 10:17 AM in reply to jcbanning

    I'm using the 74279224171 from Wurth Elektronik for now. At first glance, the frequency response looks reasonably similar to the pi filter I posted before. I don't have any actual test data that I can share right now though. 

    That said, the CN0359 actually uses narrowband modulation and delta-sigma ADCs to operate - so noise from the regulators probably won't be picked up anyway. If you have an extra CN0359, you could try shorting those EMI filters and see if the noise will affect the measurements!