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Part Number: ISOW7841
Our customer used the ISOW7841, But EMI report Fail.
Could you please support for Review Layout?
or based on EMI report Could you please provide the suggest for me?
Hi Hugo,ISOW7841 emissions are affected by factors such as layout and operating conditions. Can you include more detail of the setup? For example, what are the Vcc and Viso values? What is the load on Viso?PCB layout can greatly improve performance if designed using the considerations in this application report. Please encourage our customer to review their board layout to ensure it includes a stitching capacitor and y-capacitor as mentioned in the linked app report. Additional comments regarding common mode chokes are provided in this E2E post.Is this helpful? Please let me know!Thank you for posting on E2E,
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In reply to Manuel Chavez:
In reply to Hugo Liu:
1) Use CM choke in input and output with impedance > 1K for Freq. < 100 MHz in RE test
2) Make Stitching capacitance as per application note from TI. for Freq. > 200 MHz in RE test
3) After these changes best of luck.
In reply to Harish Gode:
In reply to Koteshwar Rao:
Thank for your explanation.
our customer tell me , VISO load <20mA(5V),
But for test COM port only have cable, the device not power on EMI is over spec.
The USB/LAN/RS232/DP connector is on same PCB, if note "EUT only" is not connect to any deice(USB/LAN/RS232/DP).
They are try to COM port metal case to GND, EMI 400~500MHz base will be reduce.
They are doubt this issue is fromCOM port ground.
we have some question, could you please share your suggest for me?
Q1, we are see the TIDA-00893 & slla368b have different equation for Ci. we can ref which one?
Q2, we are try to calculate Ci Value as below, need change to >50pF? I see the D(mm) only 0.1 any risk?
Q3, the slla368b Figure 5(RF+L1) & Figure13(Common-Mode Chokes) to reduce emissions, Is this only one on PCB or both use?
we have 4 question from customer,
could you please share your suggest for me?
Thank you very much,
I have one question from customer,
If the GND & Vcc Stacking method change to Right picture.
then effect Ci calculate or performance?
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