The REF35 voltage references are capable of source up to 10mA and sink up to 5mA of load current across the rated input voltage range. However, when used in applications subject to high ambient temperatures, the input voltage and load current must be carefully monitored to make sure that the device does not exceeded its maximum power dissipation rating. The maximum power dissipation of the device can be calculated with Equation 3:

Equation 3.

where

• P_D is the device power dissipation
• T_J is the device junction temperature
• T_A is the ambient temperature
• R_θJA is the package (junction-to-air) thermal resistance

Because of this relationship, acceptable load current in high temperature conditions can be less than the maximum current-sourcing capability of the device. In no case must the device be operated outside of its maximum power rating because doing so can result in premature failure or permanent damage to the device.