13.1 Layout Guidelines

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

13.2 Layout Example

The figure below shows an example for these devices. Notice the connection to system ground between the V_OUT Bypass Capacitor ground and the GND pin of the load switch, this creates a ground barrier which helps to reduce the ground noise seen by the device.

13.3 Thermal Considerations

The maximum IC junction temperature should be restricted to 125°C under normal operating conditions. To calculate the maximum allowable dissipation, P_D(max) for a given output current and ambient temperature, use the following equation as a guideline:

Equation 5.

where

• P_D(max) = maximum allowable power dissipation
• T_J(max) = maximum allowable junction temperature
• T_A = ambient temperature of the device
• θ_JA = junction to air thermal impedance. See the Thermal Information section. This parameter is highly dependent upon board layout.