The device is specified from –40 °C to 125 °C for a voltage rating of 2.5 V to 38 V. The part drains at its maximum current of 17 mA, therefore the maximum voltage that can be applied to the device will depend on what maximum ambient temperature is acceptable for the application. The curve in Figure 10-1 shows the maximum acceptable power supply voltage versus the maximum acceptable ambient temperature.

Use Equation 3, Equation 4, and Equation 5 to populate the data shown in Figure 10-1:

Equation 3.

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 4.

where

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

Equation 5.

where

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

Combining these equations gives Equation 6, which can be used to determine the maximum voltage the part can handle in regards of the ambient temperature.

Equation 6.

For example, if an application must work under an ambient temperature maximum of 100 °C, and the T_{J max}, R_θJA and I_{CC max} are the same values defined in the data sheet, then the maximum voltage allowed for this application is calculated in Equation 7:

Equation 7.

Figure 10-1 Power Derating Curve