3.0A Ultra Low Dropout Linear Regulator

TJ3966

Aug. 2010 - Rev. 1.7.1

- 9

-

HTC

Maximum Output Current Capability

The TJ3966 can deliver a continuous current of 3.0A over the full operating junction temperature range.

However, the output current is limited by the restriction of power dissipation which differs from packages.

A heat sink may be required depending on the maximum power dissipation and maximum ambient

temperature of application. With respect to the applied package, the maximum output current of 3.0A

may be still undeliverable due to the restriction of the power dissipation of TJ3966. Under all possible

conditions, the junction temperature must be within the range specified under operating conditions.

The temperatures over the device are given by:

The total power dissipation of the device is given by:

formula:

TJ3966 is available in SOP8-PP, TO225, TO263 and TO220 packages. The thermal resistance depends

above is over 175°C/W for SOP8-PP package, over 105 °C/W for TO252 package, over 80 °C/W for

TO263 package, over 70 °C/W for TO220 package, no heat sink is needed since the package can

these limits, a heat sink or proper area of copper plane is required.

In summary, the absolute maximum ratings of thermal resistances are as follow:

Absolute Maximum Ratings of Thermal Resistance

Characteristic

Symbol

Rating

Unit

Thermal Resistance Junction-To-Ambient / SOP8-PP

175

°C/W

Thermal Resistance Junction-To-Ambient / TO252

105

°C/W

Thermal Resistance Junction-To-Ambient / TO263

80

°C/W

Thermal Resistance Junction-To-Ambient / TO220

70

°C/W

In case that there is no cooling solution and no heat sink / copper plane area for heat sink, the maximum

allowable power dissipation of each package is as follow;