J1_x is a 1x3 header that allows the user to customize the input voltage reference of the overcurrent set point in a number of ways. Configuration options available include:

1. Short J1_x pins 1 and 2 with the supplied shorting plug: This provides the reference point with a voltage set via the potentiometer R4_x. R3_x is a 5.6kΩ resistor that forms a voltage divider with potentiometer that provides an output voltage by the following equations:
   Equation 1. ${\mathrm{V}}_{\mathrm{O}\mathrm{C}}=\frac{{\mathrm{R}}_3}{{\mathrm{R}}_{\mathrm{P}\mathrm{O}\mathrm{T}}+{\mathrm{R}}_3}{\times \mathrm{V}}_{\mathrm{S}}$
   Equation 2. ${\mathrm{f}\mathrm{o}\mathrm{r}\mathrm{ }{\mathrm{R}}_{\mathrm{P}\mathrm{O}\mathrm{T},\mathrm{ }\mathrm{m}\mathrm{a}\mathrm{x}},\mathrm{ }{\mathrm{V}}_{\mathrm{S}}=5.5\mathrm{V},\mathrm{ }\mathrm{ }\mathrm{V}}_{\mathrm{O}\mathrm{C}}=\frac{{\mathrm{R}}_3}{{\mathrm{R}}_{\mathrm{P}\mathrm{O}\mathrm{T}}+{\mathrm{R}}_3}{\times \mathrm{V}}_{\mathrm{S}}=\frac{5.60\mathrm{k}\mathrm{\Omega }}{100\mathrm{k}\mathrm{\Omega }+5.60\mathrm{k}\mathrm{\Omega }}\times 5.5\mathrm{V}=0.291\mathrm{V}\approx 0.3\mathrm{V}$
   Equation 3. ${\mathrm{f}\mathrm{o}\mathrm{r}\mathrm{ }{\mathrm{R}}_{\mathrm{P}\mathrm{O}\mathrm{T},\mathrm{ }\mathrm{m}\mathrm{i}\mathrm{n}},\mathrm{ }{\mathrm{V}}_{\mathrm{S}}=5.5\mathrm{V},\mathrm{ }\mathrm{ }\mathrm{V}}_{\mathrm{O}\mathrm{C}}=\frac{5.60\mathrm{k}\mathrm{\Omega }}{1\mathrm{k}\mathrm{\Omega }+5.60\mathrm{k}\mathrm{\Omega }}{\times \mathrm{V}}_{\mathrm{S}}=0.85\times {\mathrm{V}}_{\mathrm{S}}$

   The presence of the 5.6kΩ resistor keeps the minimum output voltage available at ≅0.3 V for the maximum device supply voltage of 5.5V. This provides a quick method on board for analyzing nearly the entire voltage range of VOC. Check VOC with a digital multimeter (DMM) for the desired voltage, adjusting R_POT higher or lower until the desired reference voltage is achieved.

2. Short J1_x pins 2 and 3 with the supplied shorting plug: This provides the reference point with the voltage produced by a resistor divider formed between R5_x and R6_x. This resistor divider is set to approximately 90% of V_S by default by the following equation, but can be customized for evaluation between any resistor pair in 0805 package within data sheet specifications.
   Equation 4. ${\mathrm{V}}_{\mathrm{O}\mathrm{C}}=\frac{{\mathrm{R}}_6}{{\mathrm{R}}_5+{\mathrm{R}}_6}{\times \mathrm{V}}_{\mathrm{S}}=\frac{88.7\mathrm{k}\mathrm{\Omega }}{98.7\mathrm{k}\mathrm{\Omega }}\times {\mathrm{V}}_{\mathrm{S}}=0.9\times {\mathrm{V}}_{\mathrm{S}}$
3. Do not populate the shorting plug: By not populating the shorting plug, the reference input VOC remains floating from any hardwired PCB input. This node is then driven directly by the VOC test point on the board to directly drive specific external voltage the user considers in their application.

The point set by any of the above methods are presented to an internal comparator, which is constantly monitored against the output voltage VOUT. In the event that VOUT > VOC, the active low nOC pin activates, pulling low to indicate that the system has reached the overcurrent point. Resistor R1_x acts as the pull up resistor for the active low nOC node.