DocID025263 Rev 5

17/25

STBB3J

Application information

7.4.3

Overtemperature protection

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

temperature exceeds 160 °C (typ.), the device stops operating. As soon as the temperature

falls below 140 °C (typ.), normal operation is restored.

8

Application information

8.1

Programming the output voltage

point of the divider must be connected to FB.

The value for the resistor R2, placed between FB and GND, should be chosen in order to

set the divider current at 1 µA. The recommended value for this resistor is in the range of

500 k

Ω but to reduce the power consumption a maximum value of 200 kΩ can be used.

voltage and can be calculated using the equation 1:

Equation 1

Figure 26. Application schematic

8.2

Inductor selection

The inductor is the key passive component for switching converters. With a buck-boost

device, the inductor selection must take into consideration the following two conditions in

which the converter works:

•

as buck region at the maximum input voltage

•

as boost region at the minimum input voltage

Two critical inductance values are then obtained according to the following formulas:

R1

R2

V

OUT

V

FB

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1

–

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×

=