LDC1614EVM: sensor

Hello, 

The LDC1614 works best with PCB coils, but if you want to debug working with a wire wound coil then I have the following questions: 

• What is the diameter of the coil? 
• How many turns are in the coil? 
• Is your coil utilizing any of the following methods? 
  • 
  • Image is from the Sensor Design for Inductive Sensing Applications Using LDC (Rev. C) app note
• What is the inductance of your coil? 
• What is the value of the capacitor you are using with it? 

Thank you, 

Justin Beigel

Diameter: 11 cm

Turns: 53

Air

550 Microhenry

4,7Nf

Sintonized in 100Khz

Hello, 

11cm is a fairly large coil size, do you know the Rp or Rs of the coil? This might be a current drive issue for the device. Have you tried putting the LDC1614 into high current drive mode? (bit 6 of the config register)

Best Regards, 
Justin Beigel

Rs = 3,2 Ohms

When I change bit6 config to 1, the signal oscilates in mode streaming.

Hello, 

Can you send an oscilloscope capture of the output for both cases (bit 6 to 0 and 1)? 

Thank you, 

Justin Beigel

config bit 6 = one

Config bit 6 = zero.

Hello, 

The captures look fairly noisy, how are you connecting to the sensor? Also, is there anything else involved in the circuit or is it just the EVM with the sensor?

Have you tried with a smaller wire coil design?  Do you still see saturation in that case? 

Best Regards, 

Justin Beigel

Only de EVM board and sensor. The red led stay on, when I disconnect the sensor the led green it´s on, and the red led it´s off. I will test with small sensor and will return.

Hello, 

What is the value of the STATUS register (0x18) and ERROR_CONFIG register (0x19) when you connect the coil? It seems like a smaller coil will likely solve this issue. Let us know once you are able to test with one. 

Thank you, 

Justin Beigel

It´s with actual sensor, I will test with small sensor, after that I will send you the result.

Hello, 

Thanks for the information. When you test with the smaller coil, can you also provide the diameter, inductance, capacitance, and Rs for that coil as well? 

Thank you, 

Justin Beigel