© Semiconductor Components Industries, LLC, 2005
September, 2005 − Rev. 1
1 Publication Order Number:
NCP4326/D
NCP4326
Secondary Controller for
Multi−Output
Quasi−Resonant
Switchmode Power
Supplies
This secondary controller significantly improves the overall
efficiency and cross−regulation figures when used in a Switchmode
Power Supply. Compared to traditional regulation schemes, the
NCP4326 provides superior performance in cross−regulation by
individually regulating outputs. Powered from a main winding, the
device actuates two independent switches that precisely adjust the
considered outputs to resistor−selectable voltages. This controller also
integrates a precision reference voltage, which together with a
dedicated operational amplifier reduces the feedback loop elements to
the minimum. In the end three independent output voltages can be
controlled by a single device.
A skip cycle feature improves the stand by power in light load
condition. Finally, dedicated shutdown pins offer an easy mean to
disable the secondary outputs in applications where a low standby
power performance is key.
Features
• 0% to 100% Duty Cycle Range
• Integrated Shunt Regulator for Optocoupler Control
• Internal Voltage Reference (1.25 V, 1% @ 25°C)
• 2 Independent Power MOSFET Drivers
• Enable/Disable for Each Driver
• Independent Soft−Starts on both Output Drivers
• Independent Skip Cycle on both Output Drivers
• Standby Pin
• 580 / 650 mA Peak Current Source/Sink Driver Capability
• Synchronization Pin
• 5 V Undervoltage Lock−Out on Vcc
• Pb−Free Package is Available
Applications
• Consumer Electronics Applications:
DVD, Set Top Box, CDR, Game Console
• Any Multi−Output Voltage Quasi−Resonant SMPS
http://onsemi.com
MARKING DIAGRAM
SOIC−16
D SUFFIX
CASE 751B
NCP4326DG
AWLYWW
1
A = Assembly Location
WL = Wafer Lot
Y = Year
WW = Work Week
G = Pb−Free Device
(Bottom View)
Device Package
Shipping
{
ORDERING INFORMATION
NCP4326DR2 3000 Tape & ReelSOIC−16
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
PIN CONNECTIONS
CP1
FB1
EN2
CP2
FB2
Ct
Sync
CPm
EN1
GND
Flux
DRV1
Vcc
DRV2
STBY
FBm
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
NCP4326DR2G 3000 Tape & ReelSOIC−16
(Pb−Free)
