TPS76201

LOW OUTPUT ADJUSTABLE

ULTRALOW-POWER 100-mA LDO LINEAR REGULATOR

SLVS323A – FEBRUARY 2001 – REVISED MAY 2001

9

POST OFFICE BOX 655303

APPLICATION INFORMATION

power dissipation and junction temperature

Specified regulator operation is assured to a junction temperature of 125

°C; the maximum junction temperature

should be restricted to 125

°C under normal operating conditions. This restriction limits the power dissipation

the regulator can handle in any given application. To ensure the junction temperature is within acceptable limits,

The maximum-power-dissipation limit is determined using the following equation:

P

D(max) +

T

J

max

* T

A

RqJA

Where:

The regulator dissipation is calculated using:

P

D +

V

I *

V

O

I

O

Power dissipation resulting from quiescent current is negligible. Excessive power dissipation will trigger the

thermal protection circuit.

regulator protection

The TPS76201 PMOS-pass transistor has a built-in back diode that conducts reverse current when the input

voltage drops below the output voltage (e.g., during power down). Current is conducted from the output to the

input and is not internally limited. If extended reverse voltage operation is anticipated, external limiting might

be appropriate.

The TPS76201 features internal current limiting and thermal protection. During normal operation, the

TPS76201 limits output current to approximately 350 mA. When current limiting engages, the output voltage

scales back linearly until the overcurrent condition ends. While current limiting is designed to prevent gross

device failure, care should be taken not to exceed the power dissipation ratings of the package. If the

temperature of the device exceeds approximately 165

°C, thermal-protection circuitry shuts it down. Once the

device has cooled down to below approximately 140

°C, regulator operation resumes.