To configure a threshold setting, connect a 49.9 kΩ resistor (R1) between VDD and the ADJ pin as shown in Figure 6-4. The threshold is determined by the value of R2 as shown in the Table 6-1 below. R1 and R2 should be 1% or tighter tolerance resistors with a temperature coefficient of <50 ppm/°C.

The switching distance for each ADJ code can be approximated with the following formula:

Equation 1.

where:

• d_switch is the approximated switching distance threshold
• d_coil is the coil diameter, in the same units as d_switch
• ADJ_Code is the desired value from Table 6-1

For example, consider a coil with a diameter of 10 mm: An ADJ code of 1 will yield a switching distance of 3.75 mm and for a code of 15 a switching distance of 0.25 mm. This method helps reduce the effort needed to design the coil ratio precisely for a specific switching distance. It should be noted that the maximum sensing distance is determined almost entirely by the diameter of the coil for circular coils or by the minimum outer dimension for rectangular coils.