DocID022745 Rev 9

17/25

STBB2

General description

7.5

Protection features

7.5.1

Soft-start and short-circuit

After the EN pin is pulled high, the device initiates the start-up phase. The average current

limit is set to 400 mA at the beginning and is gradually increased while the output voltage

increases. As soon as the output voltage reaches 1.0 V, the average current limit is set to its

nominal value.

This method allows a current limit proportional to the output voltage. If there is a short in the

timer so the device is also able to start up even with large capacitive loads.

7.5.2

Undervoltage lockout

The undervoltage lockout function prevents improper operation of the STBB2 when the

input voltage is not high enough. When the input voltage is below the VUVLO threshold, the

device is in shutdown mode. The hysteresis of 100 mV prevents unstable operation when

the input voltage is close to the UVLO threshold.

7.5.3

Overtemperature protection

An internal temperature sensor continuously monitors the IC junction temperature. If the IC

temperature exceeds 150 °C (typ.), the device stops operating. As soon as the temperature

falls below 130 °C (typ.), normal operation is restored.