DocID17928 Rev 5

3/29

ST1S40

Pin settings

29

1

Pin settings

1.1

Pin connection

1.2

Pin description

Figure 2. Pin connection (top view)

8

6

4

7

3

2

5

1

VINA

EN

FB

GND

PGND

SW

VINSW

NC

8

45

1

VINA

EN

FB

GND

PGND

SW

VINSW

AGND

VFQFPN

8

6

4

7

3

2

5

1

VINA

EN

FB

GND

PGND

SW

VINSW

NC

HSOP8

SO8-BW

9

9

HSOP-8

Table 1. Pin description

No.

Type

Description

VFQFPN

and HSOP-8

S08-BW

13

24

EN

Enable input. With EN higher than 1.2 V the device in ON and with EN lower

than 0.4 V the device is OFF (ST1S40Ixx).

35

FB

Feedback input. Connecting the output voltage directly to this pin the output

voltage is regulated at 0.8 V. To have higher regulated voltages an external

resistor divider is required from Vout to the FB pin.

4

6

AGND Ground

5

-

NC

It can be connected to ground

6

8

VINSW Power input voltage

7

1

SW

Regulator output switching pin

8

2

PGND Power ground

-

7

Ground

9

-

ePad

Exposed pad mandatory connected to ground