1A Ultra Low Dropout Linear Regulator

TJ4940

Jul. 2011 – Preliminary

6/8

HTC

APPLICATION INFORMATION

Maximum Output Current Capability

The TJ4940 can deliver a continuous current of 1A 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 1A may

be still undeliverable due to the restriction of the power dissipation of TJ4940. 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:

TJ4940 is available in SOT-223, and TO-252 packages. The thermal resistance depends on amount of

described in Table 1, no heat sink is needed since the package can dissipate enough heat to satisfy these

copper plane is required.