NCP1252 Current Mode PWM Controller for Forward and Flyback Applications The NCP1252 controller offers everything needed to build cost effective and reliable acdc switching supplies dedicated to ATX www.onsemi.com power supplies. Thanks to the use of an internally fixed timer, NCP1252 detects an output overload without relying on the auxiliary Vcc. A BrownOut input offers protection against low input voltages OFFLINE CONTROLLER and improves the converter safety. Finally a SOIC8 package saves PCB space and represents a solution of choice in cost sensitive project. Features 8 Peak Current Mode Control 1 Adjustable Switching Frequency up to 500 kHz SOIC8 PDIP8 Jittering Frequency 5% of the Switching Frequency CASE 751 CASE 626 Latched Primary Over Current Protection with 10 ms Fixed Delay SUFFIX D SUFFIX P Delay Extended to 150 ms in E Version Delayed Operation Upon Startup via an Internal Fixed Timer PIN CONNECTIONS (A, B and C versions only) Adjustable Softstart Timer 1 FB SS Autorecovery BrownOut Detection BO V CC UC384Xlike UVLO Thresholds CS DRV Vcc Range from 9 V to 28 V with Autorecovery UVLO RT GND Internal 160 ns Leading Edge Blanking (Top View) Adjustable Internal Ramp Compensation MARKING DIAGRAMS +500 mA / 800 mA Source / Sink Capability Maximum 50% Duty Cycle: A Version 8 Maximum 80% Duty Cycle: B Version 1252x 1252AP Maximum 65% Duty Cycle: C Version ALYWX AWL YYWWG Maximum 47.5% Duty Cycle: D & E Versions 1 Ready for Updated No Load Regulation Specifications SOIC8 and PDIP8 Packages x = A, B, C, D or E These are PbFree Devices A = Assembly Location L, WL = Wafer Lot Y, YY = Year Typical Applications W, WW = Work Week Power Supplies for PC Silver Boxes, Games Adapter... or G = PbFree Package Flyback and Forward Converter ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 18 of this data sheet. Semiconductor Components Industries, LLC, 2016 1 Publication Order Number: April, 2019 Rev. 8 NCP1252/DNCP1252 Vbulk Vout NCP1252 1 8 Vcc 2 7 3 6 4 5 100 nF* *Minimum recommended decoupling capacitor value Figure 1. Typical Application Table 1. PIN FUNCTIONS Pin No. Pin Name Function Pin Description 1 FB Feedback This pin directly connects to an optocoupler collector. 2 BO Brownout input This pin monitors the input voltage image to offer a Brownout protection. 3 CS Current sense Monitors the primary current and allows the selection of the ramp com- pensation amplitude. 4 R Timing element A resistor connected to ground fixes the switching frequency. T 5 GND The controller ground pin. 6 Drv Driver This pin connects to the MOSFET gate 7 V V This pin accepts voltage range from 8 V up to 28 V CC CC 8 SSTART Softstart A capacitor connected to ground selects the soft start duration. The soft start is grounded during the delay timer Table 2. MAXIMUM RATINGS TABLE (Notes 1 and 2) Symbol Rating Value Unit V Power Supply voltage, Vcc pin, transient voltage: 10 ms with I < 20 mA 30 V CC Vcc V Power Supply voltage, Vcc pin, continuous voltage 28 V CC I Maximum current injected into pin 7 20 mA Vcc V Maximum voltage on DRV pin 0.3 to V V DRV CC Maximum voltage on low power pins (except pin 6, 7) 0.3 to 10 V R Thermal Resistance JunctiontoAir PDIP8 131 C/W JA PDIP8 R Thermal Resistance JunctiontoAir SOIC8 169 C/W JA SOIC8 T Maximum Junction Temperature 150 C J(MAX) T Storage Temperature Range 60 to +150 C STG ESD ESD Capability, HBM model 1.8 kV HBM ESD ESD Capability, Machine Model 200 V MM 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: Human Body Model 1800 V per JEDEC Standard JESD22A114E. Machine Model Method 200 V per JEDEC Standard JESD22 A115A. 2. This device contains latchup protection and exceeds 100 mA per JEDEC Standard JESD78. www.onsemi.com 2