MC33063A-Q1: How to calculate the frequency of the internal oscillator?

Part Number:MC33063A-Q1

Hi,

I am trying to calculate the frequency of the internal oscillator in ordor to go through the design procedure listed in the datasheet. The problem is that it gives me answers that contradict the 100kHz max f specification. Here is my calculation with the example values in the step-down converter example:

To find the discharge time (tdis), i am using the following values:

C = 470pF
dV = 0.5V
Idis = 200mA

i then calculate:

Idis = C*dv/dt  ---->  dt = C*dv/Idis

dt = 470pF*0.5/200mA = 1ns

since the charge time is 6 times the discharge time, the period T is 7ns, which gives a frequency of approximately 143 MHz. What is happening here??