NCP1252 Datasheet, PDF (1/17 Pages) ON Semiconductor – Flyback Applications

NCP1252
Current Mode PWM
Controller for Forward and
Flyback Applications
The NCP1252 controller offers everything needed to build cost−
effective and reliable ac−dc switching supplies dedicated to ATX
power supplies. Thanks to the use of an internally fixed timer,
NCP1252 detects an output overload without relying on the auxiliary
Vcc. A Brown−Out input offers protection against low input voltages
and improves the converter safety. Finally a SOIC8 package saves
PCB space and represents a solution of choice in cost sensitive project.
Features
• Peak Current Mode Control
• Adjustable Switching Frequency up to 500 kHz
• Jittering Frequency ±5% of the Switching Frequency
• Latched Primary Over Current Protection with 10 ms Fixed Delay
• Delayed Operation Upon Start−up via an Internal Fixed Timer
• Adjustable Soft−start Timer
• Auto−recovery Brown−Out Detection
• UC384X−like UVLO Thresholds
• Vcc Range from 9 V to 28 V with Auto−recovery UVLO
• Internal 160 ns Leading Edge Blanking
• Adjustable Internal Ramp Compensation
• +500 mA / –800 mA Source / Sink Capability
• Maximum 50% Duty Cycle: A Version
• Maximum 80% Duty Cycle: B Version
• Ready for Updated No Load Regulation Specifications
• SOIC−8 Package
• This is a Pb−Free Device
Typical Applications
• Power Supplies for PC Silver Boxes, Games Adapter...
• Flyback and Forward Converter
http://onsemi.com
OFFLINE CONTROLLER
8
1
SOIC−8
CASE 751
SUFFIX D
PIN CONNECTIONS
FB
1
BO
CS
RT
SS
V_CC
DRV
GND
(Top View)
MARKING DIAGRAM
8
1252X
ALYWX
G
1
1252
X
A
L
Y
W
G
= Specific Device Code
= A or B Version
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 2 of this data sheet.
© Semiconductor Components Industries, LLC, 2009
1
April, 2009 − Rev. 1
Publication Order Number:
NCP1252/D