TPPM0302

400-mA LOW-DROPOUT REGULATOR

WITH AUXILIARY POWER MANAGEMENT AND POK

SLVS316 – NOVEMBER 2000

8

POST OFFICE BOX 655303

THERMAL INFORMATION

To ensure reliable operation of the device, the junction temperature of the output device must be within the safe

operating area (SOA). This is achieved by having a means to dissipate the heat generated from the junction

of the output structure. There are two components that contribute to thermal resistance. They consist of two

The ability to efficiently dissipate the heat from the junction is a function of the package style and board layout

incorporated in the application. The operating junction temperature is determined by the operating ambient

This particular application uses the 8-pin DGN PowerPAD package with a standard lead frame with dedicated

ground terminal. Using a multilayer printed-circuit board (PCB), the power pad is mounted as recommended

in the TI packaging application. The power pad is electrically connected to the ground plane of the circuit board

through the dedicated ground pin and the die mount power pad. This will provide a means for heat spreading

through the copper plane associated within the PCB (GND Layer). This concept could provide a thermal

Hence, maximum power dissipation allowable for an operating ambient temperature of 70

°C, and a maximum

junction temperature of 150

°C is determined as:

Using a multilayer board and utilizing the ground plane for heat spreading.

2.6

150

1.36

Power Dissipation Derate Curve Using

High-K PCB

Ambient Temperature –

°C

25

70

NOTE: This curve is to be used for guideline purposes only. For a particular application, a more specific thermal characterization is required.

Figure 12. Power Dissipation Derating Curve