Other Parts Discussed in Thread: AM5716
Tool/software:
Generally, it is un-necessary to use four different capacitor values on power input pins today. The datasheet shows use of 10,1,0.1,0.01 uF capacitor values.
Since the current draw of the IC is very small 55ma and 15ma Analog and Digital at worst case, it seems that even the use of 10uF is overdone.
I would like to know why the four capacitor values used and how the values were determined?
I would like to use 4.7uF capacitor with 0.1uF on both VDDA and VDDIO inputs, pins 3 and 17.
Ferrite bead is optional but helps since the current draw is minimal on this IC.
Please let me know your advice on using lower value Bulk Capacitor as well reducing components to 2 instead of 4.
The DP83826E has internal LDO that generate the power rails. ". An internal LDO generates all the power rails required for the device to operate"
It seems a little over the top with all the capacitor values.
Additionally, MII does not really require series resistors especially with short length paths.
I have seen EVM and other design using series resistors on RX lines and clock lines.
While this may help with reduce EMI, MII is rather slow at 25MHz and rise times in order 1n sec.
Please advise if the rise and fall times are in the datasheet or other, I could not find this specification.
The goal is to reduce component count.
This IC is used with AM5716 Sitara processor.
Your advice is greatly appreciated.
Sincerely,
David
