Demonstration board usage recommendation

AN2728

14/20

4.1

External component selection

Figure 13 shows the demonstration board schematic.

range of 500 k

Ω to 1 MΩ in order to reduce current consumption.

In order to obtain the needed output voltage, the resistor divider must be selected in

accordance with the following formula:

Equation 15

The resistors given in Table 1 are good choices in terms of current consumption.

4.2

Capacitors selection

It is possible to use any X5R or X7R ceramic capacitor:

Figure 13.

Demonstration board schematic

VFB

SW

GND

V

IN

V

OUT

2

3

EN

1

5

4

ST1S12_ADJ

L

R1

C

OUT

R2

GND

V

IN

C

IN

REN

VFB

SW

GND

V

IN

V

OUT

2

3

EN

1

5

4

ST1S12_ADJ

L

R1

C

OUT

R2

GND

V

IN

C

IN

REN

Table 1.

Recommended resistor divider

1.2 V

68 k

Ω

68 k

Ω

3.3 V

68 k

Ω

15 k

Ω

+

=

2

1

FB

OUT

R

R

1

V

V

[]

+

=

2

1

FB

OUT

R

R

1

V

V

[]