Every inductor has a distributed parasitic capacitance, which is dependent on construction and geometry. At the self-resonant frequency (SRF), the reactance of the inductor cancels the reactance of the parasitic capacitance. Above the SRF, the inductor electrically appears to be a capacitor. The parasitic capacitance is not well-controlled or stable, therefore TI recommends f_SENSOR < 0.8 × f_SR.

Figure 7-3 Example Coil Inductance vs Frequency

The example inductor in Figure 7-3, has a SRF at 6.38MHz; therefore, the inductor must not be operated above 0.8 × 6.38MHz, or 5.1MHz.