Pin

Name

Function

14

OSC

Oscillator pin. A resistor from the pin to PGND defines the switching frequency during the initial

soft-start.

15

DT

Deadtime programming. A resistor from this pin to PGND sets the deadtime during soft-start and

minimum deadtime during functional mode.

16

LEB

Leading edge blanking time programming. A resistor from this pin to ground sets the leading edge

blanking time for the ISEN comparator.

17

ISEN

Current sense (PWM comparator) input. The voltage on this pin is compared with an internal

reference to turn off LON.

18

PGND

Primary side signal ground. Reference for analog signals.

19

PUMP

Charge pump pin 1. Used to power the IC when SVCC drops below 5 V.

20

VDRV

Driver supply.

21

SRVDS

Output winding voltage sense. Connect to sync FET drain through a clamping MOSFET.

22

SRGD

Synchronous rectifier gate driver.

23

SPGND

Secondary side power ground. Current return for the sync FET gate-drive current.

24

ORGD

Load switch gate drive.

The pin controls the gate of a N type MOSFET on the positive output terminal to disconnect the

output.

25

SSGND

Secondary side signal ground.

26

CC2

USB Type-C CC2 pin. Used for USB-PD compliant communication or alternate function as

DN / GPIO3 / I2C-SCL / UART-TX.(1)

27

CC1

USB Type-C CC1 pin. Used for USB-PD compliant communication or alternate function as

DP / GPIO2 / I2C-SDA / UART-RX.(1)

28

VOSNS

Output voltage sense. Used to sense the voltage at the power supply output port (after the load

switch). The pin is used also for the bleeding function.

29

SVCC

Secondary side VCC. The device senses and controls the converter output through this pin.

30

SV3V

3.3 V Regulated supply for the IC. Connect a 1μF capacitor from this pin to SSGND.

31

SSGND

Secondary side signal ground.

32

V1V2

1.2 V regulated supply for the IC. Connect a 4.7μF capacitor from this pin to SSGND.

33

CSM

Output current sense pin. Connect to the negative side of sense resistor on the ground path.

34

CSP

Output current sense pin. Connect to the positive side of sense resistor on the ground path to sense

the current drawn by the load.

35

GPIO1

Power sharing input pin. Can be reconfigured as general purpose digital I/O, digital interface,

analog input or alternate function as

SWD-CLK / UART-TX / I2C-SCL.(2)

36

GPIO0

Power Good for the second output regulator. Can be reconfigured as general purpose digital I/O,

digital interface, analog input or alternate function as

SWDIO-TMS / UART-RX / I2C-SDA.(2)

The pin is also used to enter in programming/boot mode at IC startup. Connect a 100kΩ pullup

to SV3V to avoid unwanted entry in boot mode at startup, unless this function is configured as

disabled.

1. The firmware loaded on ST-ONEMP configures the pins as either USB-PD or programming interface. The default

configuration is USB-PD

2. Alternate functions are not supported by the preloaded firmware.

ST-ONEMP

Pin connections and description

DS13989 - Rev 2

page 4/39