------Question for C402A-FTW-LW63 Please Put your question below------
Hello all,
Hoping someone can help me. We purchased the FOCUSLCD C402A-FTW-LW63 thinking that it was the correct replacement for a current 40x2 LCD that is no longer manufactured. We found out that we require a 5vdc input and the C402A-FTW-LW63 is only a 3.3vdc input and the C402A-FTW-LW65 is the correct replacement. That being said, if the builds are the same and only the input voltage is different, wouldn’t be logical to say that the input voltage is regulated by a resistor? If I am correct, what resistor would I need to replace to convert the LW63 to the LW65 at 5vdc input voltage and where on the board is it located? I would also need the DigiKey part number for the resistor.
Thanking you in advance.
It would likely not be as simple as swapping out a resistor.
We do not have any design schematics for the display to be able to walk you through if the part can be converted to a higher voltage but it likely might be swapping out a few components including a voltage regulator.
I agree with @Kristof_2649. The LCD controller is almost certainly a different part which requires a 3.3V supply (actually 3.1V ~ 3.5V according to the datasheet) and 3.3V logic inputs.
One should not “regulate” input with a resistor. This is unreliable, as it is highly dependent on the current.
To use the 3.3V LCD with an otherwise 5V system, one would need to provide a 3.3V supply voltage, which could be taken from the 5V source and regulated down via a voltage regulator circuit like one of these.
Then, one would need to employ level shifters for each logic input pin. Here are some off-board prototype boards available to accomplish this.
Or, just go with a 5V, 40x2 LCD and be done with it.
