In the Typical Application figure, the high-side power supply (VDD1) for the AMC1200C is derived from the floating power supply of the upper gate driver.

The floating ground reference (GND1) is derived from the end of the shunt resistor that is connected to the negative input of the AMC1200C (INN). If a four-pin shunt is used, the inputs of the AMC1200C are connected to the inner leads. GND1 is then connected to the outer lead on the INN-side of the shunt. To minimize offset and improve accuracy, route the ground connection as a separate trace that connects directly to the shunt resistor. Do not short GND1 to INN directly at the device input; see the Layout Example section for more details.

Use Ohm's Law to calculate the voltage drop across the shunt resistor (V_SHUNT) for the desired measured current:

Select a RSHUNT value to satisfy the following two conditions:

• First, the voltage drop caused by the nominal current range does not exceed the recommended differential input voltage range of V_SHUNT ≤ ±250mV.
• Secondly, the voltage drop caused by the maximum allowed overcurrent does not exceed the input voltage that causes a clipping output. Keep V_SHUNT ≤ V_Clipping.