Electronic – Problem with high current draw in circuit design

current

I am working on a project where I've taken an LDC1612evm (inductance to digital converter) and removed the connected micro controller portion to communicate with a TM4C123G LaunchPad via I2C. I have been able to get the circuit working correctly when connecting the launchpad to my computer through micro usb, the circuit looking like the picture below (the pull-up resistors are for the I2C communication) enter image description here

I connected an ammeter to the LDC input to determine the current draw of the chip, which being 5mA was within the operating limits found in the datasheet. For the end product, this circuit is going to have a 12V source passed through a MC7805CT 5V regulator to control this particular section. I have attempted to simulate this as is shown in the below diagram
enter image description here

Here is where the problem occurs. When I read the ammeter I see a current of 500mA flowing into the LDC which, not surprisingly, instantly damages it.

So my question is what is causing the huge current draw?

I have checked the LDC input voltages and in both cases I get the expected 3.3V. It has been suggested that the micro controller section of the ldc1612evm has a regulator on it thus by removing that portion the regulator is bypassed allowing for the higher current draw, but from what I can tell from the launchpad's datasheet power schematic the 3.3V output contains a similar regulator, so I don't understand why that would be the problem.

Thank you in advance for any insights into the cause.

EDIT: changed out the wiring diagrams for schematics

Best Answer

Looks like LCD1612 3.3 volts is an output from a linear regulator derived from the USB and Launchpad 3.3 volts is also an output from a linear regulator. You have two voltage outputs tied together. You don't need to connect these.

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