Help understanding when to use TMR, GMR, AMR sensors

[cj23x]

I am developing a battery-powered device that needs to track the angle/rotation of a plastic component containing a small neodymium magnet using a sensor in a separate, coupled (but fixed) plastic component. A functional prototype has been developed, with the angle-tracking functionality implemented using an AMR sensor located in the “fixed” element and a simple N52 Neodymium magnet from K&J Magnetics embedded in the rotatable piece. These two parts are arranged with a separation distance of ~13.5mm such that the magnetic field lines lie parallel to the AMR sensor die (parallel to the top face of the IC). I've attached an image illustrating this configuration.

I am currently using a 130 mAh single-cell Lithium Polymer battery pack; a 3.3V LDO is used to supply the circuit, including the selected magnetic sensor. An nRF52832 SoC is being used for processing and BLE communication.

I recently realized that the AMR sensor is consuming more power than desired (~3.3mA), and while I am planning to implement a switch to toggle power to the sensor when needed, I'd like to evaluate alternative options to see if there is another component better suited to my application.

My primary question is this: For such a battery-powered application where low current consumption, sufficiently high sensitivity, and a certain degree of resolution (≤1° precision) are required, is AMR, GMR, or TMR a better choice than the others? More specifically, how does one decide which technology to use for a given application/what decision criteria are evaluated?

As a follow-up question, is there a specific product that would be recommended for me?

Happy to provide additional information if it’d be helpful. Thanks!

[Adithya_S]

Dear Valued Infineon Customer,

Thank you for reaching us out. I need to have some internal discussions with my team. 

We will come back at the earliest.

Thanks and Regards,

Adithya

[Adithya_S · Accepted solution]

Dear Valued Infineon Customer,

Hope you are doing good.

Looking into your query," AMR sensor is consuming more power than desired (~3.3mA)", I had internal discussion with my team and came up with two options which can reduce the power consumption.

Firstly, if you work with AMR based angle sensor TLE5109A16 E1210, you can select the sensor and power it ON when it is required and keep the sensor OFF when not required. Thus the average power consumed can be significantly reduce.

Secondly, TLE5501 E0001 is an Analog TMR sensor for highly accurate measurements. The typical supply current for this sensor is 1.67 mA and the maximum supply current is 2.5 mA.  Since your required current should be within 3.3mA, the supply current of this sensor lies very much in your range. This seems to be the best suite for your application. 

note:  I am attaching the supporting snapshots and links to the above description.

For TLE5109A16 E1210, look at "Application circuit for low-power consumption (e.g. turn counter)", in the datasheet at page no 13. Link:  https://www.infineon.com/dgdl/Infineon-TLE5x09A16_D-DataSheet-v02_00-EN.pdf?fileId=5546d462696dbf120...

For TLE5501 E0001, look at , "table no 11( Electrical Parameters)", in the datasheet at page no 11.Link: https://www.infineon.com/dgdl/Infineon-Infineon-TLE5501-DS-v01_00--DataSheet-v01_00-EN.pdf?fileId=55...

Coming to your second question, "How to decide when to use which technology( AMR/GMR/TMR)?". 

The answer to this question completely depends on your use and your application. The basic criteria for selection of the technology can be:

1) Requirement from sensor: In which form you require output from the sensor, i.e., whether the output is                       required in Digital format, Digital Sine/Cos and Analog Sine/Cos.

     Digital Format: Go for GMR based TLE5012B, TLE5012B(D), TLE5014(D) and TLE5014SP(D).

     Digital Sine/Cos: Go for GMR based TLE5011.

     Analog Sine/Cos: Go for GMR based TLE5009,TLE5009A16(D), TMR based: TLE5501 and AMR based: TLE5109A16(D).

2) Interface dependency: Depending on your interface with the micro-controller, select the sensor.

3) High speed and low speed applications.

Hope this clarifies,

Thanks and Regards,

Adithya