The device is specified from –40 °C to 125 °C for a voltage rating of 2.5 V to 38 V. Because the part is draining at its maximum a current of 17 mA the maximum voltage that can be applied will depend on what is the maximum ambient temperature acceptable for the application. The curve in Figure 8-22 shows the maximum acceptable power supply voltage versus the maximum acceptable ambient temperature.

The Figure 8-22 can also be calculated using the following formulas:

Equation 1.

where

• T_J is the junction temperature
• T_A is the ambient temperature
• ΔT is the difference between the junction temperature and the ambient temperature

Equation 2.

where

• P_D is the power dissipated by the part
• R_θJA is the junction to ambient thermal resistance

Equation 3.

where

• V_CC is the voltage supply of the device
• I_CC is the current consumption of the device

Combining the three equations above gives Equation 4 below:

Equation 4.

This equation gives the maximum voltage the part can handle in regards of the ambient temperature.

For example, in the application required to work within a ambient temperature of maximum 85 °C, with T_Jmax, R_θJA and I_CCmax are defined in the data sheet, the maximum voltage allowed for this application is determined in Equation 5:

Figure 8-22 Power Derating Curve