ST1L08

Application information

DocID026624 Rev 2

11/21

6

Application information

6.1

Thermal and short-circuit protections

The ST1L08 is self-protected from short-circuit condition and overtemperature. When the

output load is higher than the one supported by the device, the output current increases

until the limit of typically 1.8 A is reached, at this point the current is kept constant even

when the load impedance is zero.

Thermal protection acts when the junction temperature reaches 165 °C typical. At this point

the output of the IC shuts down. As soon as the junction temperature falls below the

thermal hysteresis value the device starts working again.

In order to calculate the maximum power that the device can dissipate, keeping the junction

temperature below the TOP, the following formula is used:

Equation 1

6.2

Output voltage setting for ADJ version

In the adjustable version, the output voltage can be set from 0.5 V up to 4 V, by connecting

a resistor divider between the ADJ pin and the output, thus allowing remote voltage

sensing.

The resistor divider should be selected using the following equation:

Equation 2

The resistors to be used, should have values in the range from 10 kΩ to 100 kΩ.

Lower values can also be suitable, but they increase current consumption.

6.3

Bias pin voltage requirements

The bias input is designed for low drop applications. The bias pin must be at least 2.7 V,

and at least 1.5 V higher than the output, to ensure proper biasing to the N-channel power

pass transistor.

6.4

External capacitors requirements

The regulator is designed to be stable with ultra low ESR ceramic capacitors on the input

and the output. The suggested minimum value of the input, bias and output capacitors is

output capacitor must also be connected as closer as possible to the output pin.