Datasheet

0.0
25.0
50.0
75.0
100.0
125.0
150.0
175.0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
Frequency (MHz)
Ls (µH)
53
LDC1612 , LDC1614
www.ti.com SNOSCY9A –DECEMBER 2014–REVISED MARCH 2018
Product Folder Links: LDC1612 LDC1614
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8.2.7 Inductor Self-Resonant Frequency
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 will electrically appear to be a capacitor. Because the parasitic
capacitance is not well-controlled or stable, it is recommended that: ƒ
SENSOR
< 0.8 × f
SR
.
Figure 63. Example Coil Inductance vs. Frequency
In Figure 63, the inductor has a SRF at 6.38 MHz; therefore the inductor should not be operated above 0.8×6.38
MHz, or 5.1 MHz.
9 Power Supply Recommendations
• The LDC requires a voltage supply within 2.7 V and 3.6 V. A multilayer ceramic X7R bypass capacitor of 1 μF
between the VDD and GND pins is recommended. If the supply is located more than a few inches from the
LDC, additional capacitance may be required in addition to the ceramic bypass capacitor. A ceramic capacitor
with a value of 10 μF is a typical choice.
• The optimum placement of bypass capacitors is closest to the VDD and GND terminals of the device. Care
should be taken to minimize the loop area formed by the bypass capacitor connection, the VDD pin, and the
GND pin of the IC. See Figure 64 for a layout example.