MC44603A_05 Datasheet, PDF (1/22 Pages) ON Semiconductor – Enhanced Mixed Frequency Mode GreenLine TM PWM Controller:Fixed Frequency, Variable Frequency,Standby Mode

MC44603A
Enhanced Mixed Frequency
Mode GreenLinet PWM
Controller:
Fixed Frequency, Variable Frequency,
Standby Mode
The MC44603A is an enhanced high performance controller that is
specifically designed for off−line and dc−to−dc converter applications.
This device has the unique ability of automatically changing operating
modes if the converter output is overloaded, unloaded, or shorted,
offering the designer additional protection for increased system
reliability. The MC44603A has several distinguishing features when
compared to conventional SMPS controllers. These features consist of
a foldback facility for overload protection, a standby mode when the
converter output is slightly loaded, a demagnetization detection for
reduced switching stresses on transistor and diodes, and a high current
totem pole output ideally suited for driving a power MOSFET. It can
also be used for driving a bipolar transistor in low power converters
(< 150 W). It is optimized to operate in discontinuous mode but can
also operate in continuous mode. Its advanced design allows use in
current mode or voltage mode control applications.
Features
• Pb−Free Packages are Available*
Current or Voltage Mode Controller
• Operation up to 250 kHz Output Switching Frequency
• Inherent Feed Forward Compensation
• Latching PWM for Cycle−by−Cycle Current Limiting
• Oscillator with Precise Frequency Control
High Flexibility
• Externally Programmable Reference Current
• Secondary or Primary Sensing7
• Synchronization Facility
• High Current Totem Pole Output
• Undervoltage Lockout with Hysteresis
Safety/Protection Features
• Overvoltage Protection Against Open Current and Open Voltage Loop
• Protection Against Short Circuit on Oscillator Pin
• Fully Programmable Foldback
• Soft−Start Feature
• Accurate Maximum Duty Cycle Setting
• Demagnetization (Zero Current Detection) Protection
• Internally Trimmed Reference
• Enhanced Output Drive
http://onsemi.com
MARKING
DIAGRAMS
16
1
16
PDIP−16
P SUFFIX
1
CASE 648
MC44603AP
AWLYYWWG
16
MC44603ADW
16
AWLYYWWG
SOIC−16
1 _{DW SUFFIX}
CASE 751G 1
A
= Assembly Location
WL = Wafer Lot
YY
= Year
WW = Work Week
G
= Pb−Free Package
PIN CONNECTIONS
V_CC 1
V_C 2
Output 3
GND 4
Foldback Input 5
Overvoltage
Protection (OVP)
6
Current Sense Input 7
Demag Detection 8
16 R_ref
15
R_Frequency
Standby
14
Voltage Feedback
Input
13 Error Amp Output
12 R_{Power Standby}
11
Soft−Start/D_max/
Voltage Mode
10 C_T
9 Sync Input
(Top View)
GreenLine Controller: Low Power Consumption in Standby Mode
• Low Startup and Operating Current
• Fully Programmable Standby Mode
• Controlled Frequency Reduction in Standby Mode
• Low dV/dT for Low EMI Radiations
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 21 of this data sheet.
*For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting
Techniques Reference Manual, SOLDERRM/D.
© Semiconductor Components Industries, LLC, 2005
1
November, 2005 − Rev. 4
Publication Order Number:
MC44603A/D