12.3 Thermal Considerations

For best performance, all traces must be as short as possible. To be most effective, the input and output capacitors must be placed close to the device to minimize the effects that parasitic trace inductances may have on normal and short-circuit operation. Using wide traces for VIN, VOUT, and GND helps minimize the parasitic electrical effects along with minimizing the case to ambient thermal impedance.

The maximum IC junction temperature must be restricted to 150°C under normal operating conditions. To calculate the maximum allowable dissipation, P_D(max) for a given output current and ambient temperature, use Equation 14.

Equation 14.

where

• P_D(MAX) is the maximum allowable power dissipation
• T_J(MAX) is the maximum allowable junction temperature (150°C for the TPS22810)
• T_A is the ambient temperature of the device
• θ_JA is the junction to air thermal impedance. Refer to the Thermal Information table. This parameter is highly dependent upon board layout.