ch343g serial communication quad lithograph

CH343 multilevel version

The use of optocoupler isolation.
Because VIO can support 1.8V, 2.5V, 3.3V and 5V, it can be connected directly, and multi-level can be achieved without optodecoupling isolation.
But the problem is that some people have reported that the 1.8V has burned the equipment, and the measured level is nothing, but I don't know why it was burned, so I made an optocoupler version.

In addition, it must be emphasized that the non-optocoupler version must be connected to the selection level short cap, otherwise there is a high probability that the CH343G will be burned directly in the access equipment! Be sure to pay attention!

The size of the reduced version is 41mm * 15mm, which is the smallest version I can shrink to.

In addition the new version without optocoupler has been cut USB for the sake of size.

New content 0: The non-optocoupler version adds a 100R current-limiting resistor to prevent excessive I/O current from burning the chip.

New content 1: Scaled-down version adds multiple 4.7K pull-up resistors to prevent annoying ESD phenomena.

New content 2: Scaled-down version and no optocoupler have been added to use the RT9011-JGPJ6 LDO level for easy soldering.

After a period of testing, make changes accordingly.

The smaller version is as follows:

No optocoupler is as follows (the current limiting resistor is on the back, which may not be safe, easy to be bumped, and requires more solder)