01-10-2019, 10:03 PM
> I am thinking about trying with the 1.2V
Is it a 2.5v mistake ?
It will not work at 1.2v
According to the results I examined,
The range of working is between "1.73v <-> 2.01v"
> ? The example schema accompanying the voltage regulator suggest to use the same value for both caps.
> Why yours are different?
You can understand if you enlarge the photo.
The value is not so important, so I adjusted it to their design value.
---
The circuit diagram presented by me is a based on examining the delivered item.
(if unless it is necessary to change)
* Ex: "Unless necessary to change"
Their design of 1.8v part is polite and further "L/C" parts for quality improvement are added.
(Like "U2: LP2985-33" of "ROCK64_ES9023_Audio_100Mbps_Ethernet_Board.pdf")
But, these parts can not be obtained.
Because the chip "L/C" can not read its value.
Moreover, these parts are considered to have little influence on essence in this case(to Network).
For the above reasons,
I did not use these parts, so I removed it from the circuit diagram.
---
I recognize that your requirement is minimizing the space.
If I were you in the same situation, I will take the following method.
That is the same constitution as "mbed-005.1.pdf".
1.8v already exists on the rock64 board.
Connect 4 terminating resistors directly to that node.
In this case, neither a regulator taking up space nor a capacitor is required.
I already tried it actually.
Tried "ROCK64" model is only "RAM=4G". (which had less margin of Ethernet)
In addition, I do not plan to check with all the "ROCK64" that i own.
And it worked.
However, in order to operate stably,
Separate "C"=(0.1 uF) was required for "TD_TCT / RD_TCT" respectively.
But, it is not a big increase in size. (+ 0.1uF x 1)
It will be possible to place on the back of the "RJ45"
It is worth to try it if you own confidence in technology.
Otherwise, let's give up.
--- Important ---
Just because I succeeded, you may not always get the same result.
Always keep this in mind.
I exhausted my physical strength considerably for English translation.
I need a little rest.
Is it a 2.5v mistake ?
It will not work at 1.2v
According to the results I examined,
The range of working is between "1.73v <-> 2.01v"
> ? The example schema accompanying the voltage regulator suggest to use the same value for both caps.
> Why yours are different?
You can understand if you enlarge the photo.
The value is not so important, so I adjusted it to their design value.
---
The circuit diagram presented by me is a based on examining the delivered item.
(if unless it is necessary to change)
* Ex: "Unless necessary to change"
Their design of 1.8v part is polite and further "L/C" parts for quality improvement are added.
(Like "U2: LP2985-33" of "ROCK64_ES9023_Audio_100Mbps_Ethernet_Board.pdf")
But, these parts can not be obtained.
Because the chip "L/C" can not read its value.
Moreover, these parts are considered to have little influence on essence in this case(to Network).
For the above reasons,
I did not use these parts, so I removed it from the circuit diagram.
---
I recognize that your requirement is minimizing the space.
If I were you in the same situation, I will take the following method.
That is the same constitution as "mbed-005.1.pdf".
1.8v already exists on the rock64 board.
Connect 4 terminating resistors directly to that node.
In this case, neither a regulator taking up space nor a capacitor is required.
I already tried it actually.
Tried "ROCK64" model is only "RAM=4G". (which had less margin of Ethernet)
In addition, I do not plan to check with all the "ROCK64" that i own.
And it worked.
However, in order to operate stably,
Separate "C"=(0.1 uF) was required for "TD_TCT / RD_TCT" respectively.
But, it is not a big increase in size. (+ 0.1uF x 1)
It will be possible to place on the back of the "RJ45"
It is worth to try it if you own confidence in technology.
Otherwise, let's give up.
--- Important ---
Just because I succeeded, you may not always get the same result.
Always keep this in mind.
I exhausted my physical strength considerably for English translation.
I need a little rest.
