Cirrus Logic AN353 - Manual (Page 2)

AN353
2
It is a general recommendation that a resistor (R
CS
) is used in series between the CS pin & the sense resistor (R
Sense
). The time
constant (T
CS
) of this should not be greater than 10ns. This number indicates the delay the PCB circuitry adds and would linearly
add to the inherent delay in turning the gate off upon an overcurrent event.
The maximum capacitance that can be used is 1nF, assuming R
Sense
= 0.1 . The equation for the current-sense filter capaci-
tance is:
C
CS
= T
CS

R
CS
Setting R
CS
to be 100 , the equation yields:
C
CS
= 100pF.
Therefore, the recommended capacitance for the current-sense filter is 100pF.
R
sense
R
cs
C
cs
CS1601
4 CS
Figure 1. Current Sense Filter