NCP4302
www.onsemi.com
2
PIN DESCRIPTION
Pin
Number
Symbol Description
1 SYNC/CS Connected to the flyback winding. The current on this pin is sensed and used to turn on the Synchronous
Rectification MOSFET (SRFET). This pin is also used to sense the zero crossing of the MOSFET current
either using the R
DS(on)
of the SRFET or using an external current sense resistor connected between
drain of the SRFET and the flyback winding.
2 TRIG Input pin for direct turn−off of the MOSFET. Typically connected to a signal from primary controller (for
CCM mode) or a signal derived from the transformer (for QR mode). Has very short propagation delay to
output (<50 ns).
3 CATH Feedback compensation pin for the TL431 shunt regulator. Has the capability to sinking 10 ma of opto
current.
4 V
REF
Output voltage feedback through resistive divider connected to this pin. Regulated at 1.28 V (option B) or
2.55 V (option A).
5 D
LYADJ
A resistive divider between the power supply output and ground with the center point tied to the D
LYADJ
input pin allows for independent adjustment of the minimum t
on
and t
off
delay time. The maximum extern-
al capacitance from this pin to ground is 25 pF.
6 GND Return pin for the controller – connected to the output return.
7 DRV Drive output for external MOSFET – 2.5 A peak drive capability, internally clamped to 13.5 V (Maximum)
8 V
CC
Bias voltage for the controller. Maximum voltage is 28 V.
MAXIMUM RATINGS
Rating Symbol Value Unit
Power Supply Input
Current
V
CC
I
CC
−0.3 to 28
100
V
mA
Drive Voltage
Current
V
DRV
−0.3 to 18
100
V
mA
Drive Current
Source
Sink
I
DRV
2.5
−2.5
Apk
Analog and Logic Inputs TRIG, V
REF
,
D
LYADJ
−0.3 to 10
100
V
mA
Maximum Voltage
Current
SYNC/CS − 10 to 95
100
V
mA
Operating Junction Temperature Range T
J
−40 to 125 °C
Maximum Junction Temperature T
Jmax
150 °C
Storage Temperature Range T
Smax
−65 to 150 °C
Lead Temperature (Soldering, 10 s) T
Lmax
300 °C
Reference input Current, continuous I
REF
−0.05 to 10 mA
Total Power Dissipation P
D
225 mW
Thermal Resistance Junction−to−Ambient
q
JA
178 °C/W
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.
1. This device series contains ESD protection and exceeds the following tests:
Pin 1−8: Human Body Model 2000 V per JEDEC Standard JESD22, Method A114E.
Machine Model (MM) 200 V per JEDEC Standard JESD22, Method A115A.
2. This device contains Latch−up protection and exceeds ±100 ma per JEDEC Standard JESD78
