2

Pin connections and description

Figure 3. Pin connection (top view)

HV

nc

nc

nc

DT

LEB

OVP

PVCC

PGND

P3V3

HON

LON

EN_OUT

SS

OSC

POTP

ISEN

PGND

GPIO0

GPIO1

SSGND

CSP

CSM

VDRV

V1V2

SV3V

SVCC

SRVDS

SSGND

VOSNS

CC1

CC2

SPGND

SRGD

PUMP

ORGD

Table 1. Pin functions

Pin

Name

Function

1

HV

High voltage start-up generator / ac voltage sensing input. The pin, able to withstand 800 V, must be

connected to the ac side of the input bridge via a pair of diodes to sense the ac input voltage.

When the voltage on the pin is higher than VHVStart, an internal pull-up circuit charges the capacitor

connected between the pin PVCC and PGND.

The pin is used also to sense the ac voltage, which is used by ac brown-out and X-cap discharge

functions.

2,3,4

nc

High voltage spacer. The pin is not connected internally to increase spacing between the high-

voltage pin and the other pins.

5

POTP

Primary side overtemperature protection. Pulling this pin below VPOVTH shuts down the IC.

6

SS

Soft-start setting. Connect a capacitor to PGND to set the soft-start duration.

7

OVP

Aux winding sense for overvoltage protection.

8

PVCC

Primary side supply voltage pin. The internal high voltage generator allows to charge an external

capacitor connected between this pin and PGND before the converter starts up. A small bypass

capacitor (0.1 µF typ.) to PGND must be placed close to the pins to get a clean bias voltage.

9

PGND

Primary side ground. Reference for I/Os.

10

P3V3

Primary side internal supply regulator bypass capacitor.

11

HON

High-side gate-drive control signal.

12

LON

Low-side gate-drive control signal.

13

EN_OUT

Enable signal for an external driver. Improves efficiency during bursts in case the driver supports

this functionality.

ST-ONEMP

Pin connections and description

DS13989 - Rev 2

page 3/39