NCV8877

www.onsemi.com

2

Figure 1. Typical Application

BATTERY

IN

DISABLE

CC

RC

ROSC

CDRV

Q

DB

LP

VDRV

GND

ISNS

ROSC

VOUT

DISB

GDRV

VC

RSNS

Co

Cg

VOUT

Figure 2. Functional Waveforms

Wake Up Threshold

Wakeup

DISB

(Internal signal)

Battery In

VOUT

Regulation

Sleep Threshold

GDRV

Wake Up Delay

COMP

GDRV Switching Delay

Internal Clamp

Voltage

PACKAGE PIN DESCRIPTIONS

Pin No.

Pin

Symbol

Function

1

DISB

Disable input. This part is disabled when this pin is brought low.

2

ISNS

Current sense input. Connect this pin to the source of the external N−MOSFET, through a current−sense res-

istor to ground to sense the switching current for regulation and current limiting.

3

GND

Ground reference.

4

GDRV

Gate driver output. Connect to gate of the external N−MOSFET. A series resistance can be added from GDRV

to the gate to tailor EMC performance.

5

VDRV

Driving voltage. Internally−regulated supply for driving the external N−MOSFET, sourced from VOUT. Bypass

with a 1.0

mF ceramic capacitor to ground.

6

VOUT

Monitors output voltage and provides IC input voltage.

7

VC

Output of the voltage error transconductance amplifier. An external compensator network from VC to GND is

used to stabilize the converter.

8

ROSC

Use a resistor to ground to set the frequency.