PIN

NAME

DESCRIPTION

APPLICATION INFORMATION

9

SYNC

Synchronization input

A low impedance current input pin. The current into this pin sets

the RAMP capacitor charge current and the frequency of an

internal oscillator that provides a clock for the free-run (DC

input) mode .

10

PGND

Power Ground

Connect directly to the analog ground pin (AGND).

11

LO

Low side gate driver output

Connect to the gate of the low side synchronous MOSFET

through a short low inductance path.

12

VCC

Output of bias regulator

Nominal 7V output from the internal LDO bias regulator. Locally

decouple to PGND using a low ESR/ESL capacitor located as

close to controller as possible.

13

HS

High side MOSFET source connection

Connect to negative terminal of the bootstrap capacitor and the

source terminal of the high side MOSFET.

14

HO

High side gate driver output

Connect to the gate of high side MOSFET through a short low

inductance path.

15

HB

High side gate driver bootstrap rail

Connect to the cathode of the bootstrap diode and the positive

terminal of the bootstrap capacitor. The bootstrap capacitor

supplies current to charge the high side MOSFET gate and

should be placed as close to controller as possible.

16

VBIAS

Supply Bias Input

Input to the LDO bias regulator that powers internal blocks..

Input range of VBIAS is 4.5V to 30V.

-

Exposed Pad

(LLP

Package

Only)

Exposed Pad, underside of LLP package Internally bonded to the die substrate. Connect to system

ground for low thermal impedance.

www.national.com

3