SC419

9

Pin Descriptions

Pin #

Pin Name

Pin Function

1

FB

Feedback input for switching regulator — connect to an external resistor divider from output — used to

program the output voltage.

2

NC

No Connection

3

VDDA

Supply input for internal analog circuits — connect to 5V supply — and the sense input for VDDA UVLO.

Bypass with a 100nF minimum capacitor to AGND.

4

VOUT

Output voltage sense pin

5

NC

No Connection

6

VIN

Input supply voltage — connect to the same supply as the high-side MOSFET. Connect a 100nF capacitor to

AGND.

7

NC

No Connection

8

BST

Bootstrap pin — connect a 100nF minimum capacitor from BST to LX to develop the floating voltage for the

high-side gate drive.

9

DH

High-side gate drive output

10

LX

Switching (phase) node

11

PGND

Power ground

12

DL

Low-side gate drive output

13

VDDP

Supply input for the DH and DL gate drives — connect to the same 5V supply used for VDDA. Bypass with a

1μF minimum capacitor to PGND.

14

PSV

Power-save programming input — connect a resistor to AGND to set the minimum power-save frequency.

Float pin to select power-save at no minimum frequency or pull up to VDDA to disable power-save.

15

PGOOD

Open-drain Power Good indicator — high impedance indicates the switching regulator output power is

good. An external pull-up resistor is required.

16

ILIM

Current limit sense pin — used to program the current limit by connecting a resistor from ILIM to LX.

17

EN

Enable input for switching regulator — logic low disables the switching regulator or logic high enables the

switching regulator.

18

AGND

Analog ground

19

TON

ON time programming input — set the on-time by connecting through a resistor to AGND.

20

AGND

Connect this pin to AGND along with pins 18 and PAD.

PAD

AGND

Analog ground