Thermal hysteresis for the REF33xx is defined as the change in output voltage after operating the device at 25°C, cycling the device through the specified temperature range, and returning to 25°C. It can be expressed as Equation 1:
Equation 1.
where
- VHYST = thermal hysteresis (in units of ppm).
- VNOM = the specified output voltage.
- VPRE = output voltage measured at 25°C pretemperature cycling.
- VPOST = output voltage measured after the device cycles from 25°C through the specified temperature range of –40°C to 125°C and returns to 25°C.