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
PWM
+
R
C
C
C
R
SNS
R
F1
V
ref
C
DRV
R
F2
V
g
V
o
C
g
C
o
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
from GDRV to the gate to tailor EMC performance. An R
GND
= 15 kW (typical) GDRV−GND resistor is
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.
ABSOLUTE MAXIMUM RATINGS (Voltages are with respect to GND, unless otherwise indicated)
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.
