An integrated circuit can include at least one slew generator circuit comprising at least one body biasable reference transistor, the slew generator circuit configured to generate at least a first signal having a slew rate that varies according to characteristics of the reference transistor; a pulse generator circuit configured to generate a pulse signal having a first pulse with a duration corresponding to the slew rate of the first signal; and a counter configured to generate a count value corresponding to a duration of the first pulse.