uummmm, dificil eso, a lo sumo encontraras un curva o algo parecido
lo siguiente es lo q dice el datasheet ,
son tantas als dependencias q no se podria generar una formula.....
y la presicion y deriva son un desastre..
For timing insensitive applications, the “RC” device
option offers additional cost savings. The RC oscillator
frequency is a function of the supply voltage, the resistor
(REXT) and capacitor (CEXT) values, and the operating
temperature. In addition to this, the oscillator
frequency will vary from unit to unit due to normal process
parameter variation. Furthermore, the difference
in lead frame capacitance between package types will
also affect the oscillation frequency, especially for low
CEXT values. The user also needs to take into account
variation due to tolerance of external R and C components
used.
Suerte.