ncv8871 ON Semiconductor, ncv8871 Datasheet - Page 2

• Manufacturer Part Number: ncv8871
• Description: Ncv8871 Automotive Grade Non-synchronous Boost Controller
• Manufacturer: ON Semiconductor

SYNC
PACKAGE PIN DESCRIPTIONS
EN/
Pin No.
1
2
3
4
5
6
7
8
R
C
EN/SYNC
C
C
EN/SYNC
Symbol
GDRV
VDRV
ISNS
GND
VFB
VIN
Pin
VC
VC
1
7
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.
Current sense input. Connect this pin to the source of the external N−MOSFET, through a current−sense
resistor to ground to sense the switching current for regulation and current limiting.
Ground reference.
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.
Driving voltage. Internally−regulated supply for driving the external N−MOSFET, sourced from VIN. Bypass
with a 1.0 mF ceramic capacitor to ground.
Input voltage. If bootstrapping operation is desired, connect a diode from the input supply to VIN, in addi-
tion to a diode from the output voltage to VDRV and/or VIN.
Output of the voltage error amplifier. An external compensator network from VC to GND is used to stabilize
the converter.
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.
Figure 1. Simplified Block Diagram and Application Schematic
OSC
SC
TEMP
FAULT
LOGIC
+
http://onsemi.com
CLK
SCP
SS
CL
2
LOGIC
DRIVE
CSA
Gm
Function
V
VDRV
ref
6
5
4
2
3
8
VIN
VDRV
GDRV
ISNS
GND
VFB
C
DRV
R
SNS
L
Q
R
R
D
F1
F2
C
C
o
g
V
V
g
o