If placed on the input to the boost converter, a CSM with a lower CMR can be selected. However, placing the CSM on the output bypasses the boost inductor and facilitates a faster reaction time to a short condition. Regardless of where the CSM is placed, an RC filter should be used to attenuate noise and resonance ringing that may occur as a result of abrupt di/dt events through the shunt resistor. A small 100Ω resistor and differential capacitor can be placed with a time constant three times larger than the estimated Lp/R time constant of the shunt where Lp is the parasitic shunt inductance. Since the gain error and bandwidth of the CSM is adversely affected by this noise filter, it is important to keep the filter value small.