A capacitor to VIN on the CT pin sets the slew rate of V_OUT. The CT capacitor voltage ramps until shortly after the switch is turned on and V_OUT becomes stable.

Leaving the CT pin open results in the highest slew rate and fastest turn-on time. These values can be found in the Switching Characteristics Table. For slower slew rates the required CT capacitor can be found using Equation 1:

where

• Slew Rate = desired slew rate (mV/us)
• CT = the capacitance value on the CT pin (pF)
• SR_ON = slew rate constant from table [(mV/μs) × pF]

The total turn-on time has a direct correlation to the output slew rate. The fastest turn on times (t_ON), with CT pin open, can be found in the Switching Characteristics. For slower slew rates, the resulting turn-on time can be found with Equation 2:

where

• Turn-On Time = total time from enable until V_OUT rises to 90% of V_IN (μs)
• CT =the capacitance value on the CT pin (pF)
• t_ON = Turn-On time constant (μs/pF)