8.2 Thermal Hysteresis
Thermal hysteresis for the device 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. Thermal hysteresis was measured with the REF60xx soldered to a PCB, similar to a real-world application. The PCB was baked at 150°C for 30 minutes before thermal hysteresis was measured. Thermal hysteresis is expressed as:
- 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 has cycled from 25°C through the specified temperature range of –40°C to 125°C and returns to 25°C.
Typical thermal hysteresis distribution is shown in Figure 42 and Figure 43.
Figure 42. Thermal Hysteresis Distribution (Cycle 1)
Figure 43. Thermal Hysteresis Distribution (Cycle 2)