Application information

STCS2

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8

Application information

8.1

Reverse polarity protection

STCS2 must be protected from reverse connection of the supply voltage. Since the current

protect the chip. Care must be taken for the whole application circuit, especially for the

voltage will be applied to the LED string that must have a total breakdown voltage higher

than the negative applied voltage in order to avoid any damage.

8.2

Thermal considerations

The STCS2 is able to control a LED current up to 2 A and able to sustain a voltage on the

drain pin up to 40 V. Those operating conditions are however limited by thermal constraints.

The poor thermal conduction of epoxy FR4 boards does not permit to benefit of the

outstanding thermal performance of the PowerSO-10.

In any case one way to improve the thermal conduction is the use of large heat spreader

areas at the copper layer of the PC board. This leads to a reduction of thermal resistance to

Use of copper-filled through holes on conventional FR4 techniques increases the

metallization and decreases thermal resistance accordingly. Using a configuration with 16

holes under the spreader of the package with a pitch of 1.8 mm and a diameter of 0.7 mm,

the thermal resistance (junction - heatsink) can be reduced to 12 °C/W.

The thermal resistances shown in the Error! Reference source not found. section are the

typical ones.

The power dissipation in the device can be calculated as follow:

Figure 11.

Reverse polarity condition

PWM

EN

GND

V

CC

DRAIN

DISC

FB

+

or similar

BAT46

RSENSE

SOURCE

PWM

EN

GND

V

CC

DRAIN

DISC

FB

+

or similar

BAT46

RSENSE

SOURCE