NCV8870

www.onsemi.com

2

Gm

8

3

2

4

6

GND

ISNS

GDRV

VIN

VFB

5

VDRV

CSA

OSC

Q

D

L

SC

TEMP

VDRV

DRIVE

LOGIC

CL

SCP

SS

FAULT

LOGIC

CLK

1

EN/SYNC

EN/

SYNC

7

VC

+

Figure 1. Simplified Block Diagram and Application Schematic

PACKAGE PIN DESCRIPTIONS

Pin No.

Pin Symbol

Function

1

EN/SYNC

Enable and synchronization input. The falling edge synchronizes the internal oscillator. The part is

disabled into sleep mode when this pin is brought low for longer than the enable time-out period.

2

ISNS

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

rent-sense resistor 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

strongly recommended.

5

VDRV

Driving voltage. Internally-regulated supply for driving the external N-MOSFET, sourced from VIN.

Bypass with a 1.0

mF ceramic capacitor to ground.

6

VIN

Input voltage. If bootstrapping operation is desired, connect a diode from the input supply to VIN,

in addition to a diode from the output voltage to VDRV and/or VIN.

7

VC

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

stabilize the converter.

8

VFB

Output voltage feedback. A resistor from the output voltage to VFB with another resistor from VFB to

GND creates a voltage divider for regulation and programming of the output voltage.

Rating

Value

Unit

Dc Supply Voltage (VIN)

−0.3 to 40

V

Peak Transient Voltage (Load Dump on VIN)

45

V

Dc Supply Voltage (VDRV, GDRV)

12

V

Peak Transient Voltage (VFB)

−0.3 to 6

V

Dc Voltage (VC, VFB, ISNS)

−0.3 to 3.6

V

Dc Voltage (EN/SYNC)

−0.3 to 6

V

Dc Voltage Stress (VIN − VDRV)*

−0.7 to 40

V

Operating Junction Temperature

−40 to 150

°C

Storage Temperature Range

−65 to 150

°C

Peak Reflow Soldering Temperature: Pb−Free, 60 to 150 seconds at 217

°C

265 peak

°C

Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality

should not be assumed, damage may occur and reliability may be affected.

*An external diode from the input to the VIN pin is required if bootstrapping VDRV and VIN off of the output voltage.