Part Number: ISO1042-Q1
I'd like to ask you on measurement of input capacitance (CANH/CANL) that says in datasheet page 10 of ISO0142-Q1. Please let me know how to measure this input capacitance of datasheet, and share the related document with me. I think that measurement method of datasheet is different from my customer's measurement method. Please refer to the attached file below. Could you explain on the difference of both?
Measurement of input capacitance.pdf
This is another thread with a similar question that has been answered. It is advised to measure the capacitance in the device's operational state and with a frequency greater than 5kHz. CAN bus communication will be much higher than this so it is advised to measure at around 1MHz.
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In reply to Lucas Schulte9:
Thanks for your support. I saw an another e2e thread that you told me on previous post. It will help me and my customer understand the biasing network of CAN transceiver. I will ask you some questions if I have some issues.
In reply to Jeffrey Chung1:
I am marking this as resolved for now but please feel free to ask questions if you need further assistance.
I need to ask you some more questions. My customer is testing the internal capacitance of CANH, CANL, and short to CANH & CANL through LCR meters under condition of VCC2(Pin 8) = 5V, CANH(Pin 7) or CANL(Pin 6) or CANH(Pin 7) & CANL(Pin 6) = connect to LCR meters, and GND2(Pin 5) = connect to LCR meters. Test results are as follows. CANH(Pin 7) only is 44.99pF, CANL(Pin 6) only is 42.77pF, and CANH(Pin 7) & CANL(Pin 6) is 87.63pF. Is there any problem? or Measurement method through LCR meters is correct?
Also, I want to know the device's operational state that you told me on previous post. Please let me know the details.
What frequency is the LCR using to make measurements? To replicate typical operating conditions, the frequency should be around 1MHz.
The device's typical operational state would be powered on and transmitting between 1Mbps and 5Mbps. Since capacitance is a function of frequency, it then makes sense to take measurements at 1MHz since that would be within the typical range of communication speed in most applications.
The frequency of LCR meter is 1kHz. They will test the capacitance as a changed frequency.
Also, It says that ISO1042-Q1 meets the ISO 11898-2:2016 physical layer standard in datasheet. Is there any test result document or related document? Please share it with me.
Yes please have the customer test with 1MHz instead of 1kHz.
I will respond about the ISO standard on Monday after I discuss this with my team.
I have information on the ISO 11898-2:2016 test standard for the ISO1042-Q1 but I can't share it on the forum. I can email it to you if you accept my friend request.
Thanks for your support. I have already accepted your friend request. So you can email me it. I'll waiting for your email.
The information has been sent over email and we discuss the issue further if needed also over email.
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