LDC1614: Using just the tiny chip with Arduino (without EVM board)

Ahmed Zohaib Zaidi

Part Number: LDC1614

Tool/software:

I’m working on a project where I need to measure a distance of 15 mm between a sensing coil and a metal target. While I’ve already ordered the LDC1614EVM evaluation board and I know it can be interfaced with an Arduino, I’d prefer not to use it as it makes the circuit bulkier. Instead, I want to design a custom PCB using the tiny LDC1614 (4 mm x 4 mm x 1 mm) chip and connect it directly to an Arduino Nano.

Is it feasible to create this compact setup with the LDC1614, or are there any challenges I should consider?

Thanks,
Ahmed

7 months ago

0 John Miller - Sensing 7 months ago

TI__Mastermind 40295 points

Ahmed,

Thanks for the post and your interest in TI Inductive Sensor AFEs Inductive Sensor AFEs.

You can certainly create a compact PCB. The easiest approach might be to try to merge the Arduino layout and the analog portion of the LDC1614 LDC1614EVM layout.
One thing to pay particular attention to is the PCB grounding around the LDC and the traces that connect the LDC to your sense coil. try to have ground places beneath the LDC and the traces that connect the LDC to the sense coils. Be sure the grounds have low-resistance, direct and solid connections to the connection where GND comes onto the PCB.
App note (5) below covers some aspects of PCB best-practices.

One good place to start for more info would be the [E2E FAQ] Inductive sensing FAQ - Frequently asked questions page.

Other collateral to consider are the app notes:

There's also an Excel-based tool that gives a starting point for sensor designs and device settings: Inductive Sensing Design Calculator Tool

Your university may have access to EM simulation tools like ANSYS or COMSOL, but if they don't, there's a free tool called FEMM you can download & use.
An app note that describes how to use FEMM to simulate inductive sensors is Simulate Inductive Sensors Using FEMM (Finite Element Method Magnetics).

You can see a list of other collateral in the LDC1614 Product Folder.

I hope this helps.

Please let me know if you have any questions.

Regards,
John

0 Ahmed Zohaib Zaidi 7 months ago in reply to John Miller - Sensing

Prodigy 10 points

Thank you for replying to my query. It is really helpful. While I am reading the material that you suggested to get a detailed knowledge of this technology, I have a few questions:
1. The analog portion of the LDC EVM (please refer to the image below) is in the red rectangle, correct? Can I cut the other two portions on the left and right to reduce the size? So, I just connect the sensing coil along with the dedicated capacitor at CH0, CH1, CH2 and CH3?
2. Using this analog portion, I can only use four sensing coils, correct? In future, I would like to use more sensors in which case will I have to resort to the tiny chips with a dedicated PCB?

0 John Miller - Sensing 7 months ago in reply to Ahmed Zohaib Zaidi

TI__Mastermind 40295 points

Ahmed,

Your red rectangle does indeed identify the analog circuitry, and you can break off the portions to the left and right of the rectangle.
The left side provides power, GND, and the I2C interface, so if you remove that, you will need some other way to provide power, GND, and a way to "talk" to the LDC1614.

The right side is two sense coils. If you remove the right side, you will need to replace it with some other sense coils.
You can support up to four coils.
If you want more than four channels, you will need more devices.

Regards,
John

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LDC1614: Using just the tiny chip with Arduino (without EVM board)