The PCB copper area acts as a heat sink. The footprint copper pads should be as wider as possible to spread

and dissipate the heat to the surrounding environment. Thermal vias to the inner or backside copper layers

improve the overall thermal performance of the device.

The power dissipation of the LDO depends on the input voltage, output voltage and output current, and is given

by:

Equation 2

The junction temperature of the device is:

Equation 3

resistance junction-to-ambient.

With the above equation it is possible to calculate the maximum allowable power dissipation, therefore the

maximum load current for a certain voltage drop. Appropriate de-rating of the operating condition can be applied

accordingly.

7.5

Protection features

Current limit

The STLQ020 embeds a constant-current limit circuit, which acts in case of overload or short-circuit on the output,

clamping the load current to a safe value (typ. 380 mA).

Normal operation is restored if the overload disappears, but prolonged operation in current limit may lead to high

power dissipation inside the LDO and subsequently to thermal shutdown.

Thermal protection

An internal thermal feedback loop disables the output voltage if the die temperature reaches approximately

160 °C. This feature protects the device from excessive temperature that could lead to permanent damage to the

LDO.

Once the thermal protection is triggered and the device is shut down, normal operation is automatically recovered

if the die temperature falls below 140 °C (thermal protection hysteresis of 20 °C typically)

Important note: to keep the device power consumption below 500 nA in low load/no load condition, the internal

thermal protection is kept disabled for load current below 1 mA.

Current and thermal limit protections are designed to protect the LDO from excessive power dissipation and not

intended to replace a proper thermal and electrical design of the application.

Continuous operation above the maximum ratings may lead to permanent damage to the device.

STLQ020

Protection features

DS12072 - Rev 3

page 14/31