Empty Footprint back side of 16x2 LCD display - What is the unpopulated component ?

Jayant's picture

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Empty Footprint back side of 16x2 LCD display - What is the unpopulated component ?
August 6, 2020 - 1:30pm

Hey, 

I have been using 16x2 LCD display for a long time, but now i notice something new. There are some new footprints at the backside of the LCD for a IC and few capacitors and jumpers. So does anyone here know what these footprints are for?

I am adding the picture below for your reference 

16x2 LCD empty footprint.PNG

Sourav Gupta's picture

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Those are used to add additional address id using the U3 chip, in such case the Jumper J1, J2 and J3 needs to be changed or needs to be configured.

This is unpopulated because it is not required but the manufacturer used the footprint if this is required in future or had been used in the past but changed due to the changes in mcu technology U1 and U2.

Jayant's picture

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I can clearly see for myself that U3 is for an IC chip and J1, J2 J3 are for jumpers which has to be changed based on aplication. 

But, my question is why is U3 not occupied? When should I use U3 and what IC will go there?

I am able to get my LCD working normally with Arduino uno, just qurious to know why this option is there on the LCD

Aswinth Raj's picture

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You can use a switched-capacitor voltage converter like the L7660 or MAX660 IC in place of U3 and operate the LCD module with only 3.3V operating voltage. It will be useful when you do not have a 5V voltage available for your design. The capacitor C1 and C2 are just 10uF cap that supports the working of voltage converter IC. Also when using in 3.3V mode Jumper J1 should be opened and J3 should be closed 

By default without any change the LCD is will work fine on 5V systems, like in your case it works normal with the arduino uno 

 

Sourav Gupta's picture

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Ashwinth is right. I was wrong. I should give it a try and check the output... Got something interesting.