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PT2305 V1.1

- 7 -

May, 2005

2.5W × 2 Class AB Audio Power Amplifier

PT2305

HEAT DISSIPATION

During normal operation, the chip only consumes very little stand-by current. In high output power

conditions, the package temperature will rise. For proper operating temperature, a modest heat sink

mounted on the top side of the chip is required. The thermal resistance requirement of the heat sink

demand may be obtained by the formula below:

With 60% estimated efficiency (eff), PT2305 in 2W + 2W output power dissipation is probably

The maximum chip conjunction temperature is 150

°C. Exceeding this temperature will damage the

chip, assuming the outside environment air temperature is 50

°C. From the chip conjunction dissipation

to external environment thermal resistance

θJA should be:

The PT2305 chip conjunction to case thermal resistance

θJC is 26℃ /W. Therefore the heat sink

thermal resistance should be:

In normal operating, no need extra heat sink, only utilize the ground (copper foil) of PCB to heat

dissipation.