NCP1251 Current-Mode PWM Controller for Off-line Power Supplies The NCP1251 is a highly integrated PWM controller capable of delivering a rugged and high performance offline power supply in a www.onsemi.com tiny TSOP6 package. With a supply range up to 28 V, the controller hosts a jittered 65 kHz or 100 kHz switching circuitry operated in peak MARKING DIAGRAM current mode control. When the power on the secondary side starts to decrease, the controller automatically folds back its switching TSOP6 frequency down to a minimum level of 26 kHz. As the power further (SOT236) 5xyAYW goes down, the part enters skip cycle while limiting the peak current. SN SUFFIX Over Power Protection (OPP) is a difficult exercise especially when CASE 318G 1 1 STYLE 13 noload standby requirements drive the converter specifications. The ON proprietary integrated OPP lets you harness the maximum 5xy = Specific Device Code delivered power without affecting your standby performance simply x = A or U y = A, 2, C, D, or F via two external resistors. A latched Over Voltage Protection (OVP) is A = Assembly Location combined on the same pin. For ease of implementation, a latched OVP Y = Year also monitors the V line. They offer an efficient protection in case CC W = Work Week of optocoupler destruction or adverse open loop operation. = PbFree Package Finally, a timerbased shortcircuit protection offers the best (Note: Microdot may be in either location) protection scheme, letting you precisely select the protection trip point irrespective of a loose coupling between the auxiliary and the power windings. PIN CONNECTIONS Features GND 1 6 DRV FixedFrequency 65 or 100 kHz CurrentMode Control Operation FB 2 5 V CC Internal and Adjustable Over Power Protection (OPP) Circuit Frequency Foldback Down to 26 kHz and SkipCycle in Light Load OPP/Latch 3 4 CS Conditions (Top View) Internal Ramp Compensation Internal Fixed 4 ms SoftStart 100 ms TimerBased AutoRecovery ShortCircuit Protection ORDERING INFORMATION See detailed ordering, marking and shipping information on Frequency Jittering in Normal and Frequency Foldback Modes page 2 of this data sheet. Option for AutoRecovery or Latched ShortCircuit Protection OVP Input for Improved Robustness Up to 28 V V Operation CC Latched or AutoRecovery OVP Protection on V CC +300 mA / 500 mA Source/Sink Drive Capability Less than 100 mW Standby Power at High Line EPS 2.0 Compliant These are PbFree Devices Typical Applications acdc Converters for TVs, Settop Boxes and Printers Offline Adapters for Notebooks and Netbooks Semiconductor Components Industries, LLC, 2015 1 Publication Order Number: June, 2015 Rev. 14 NCP1251/DNCP1251 Vbulk Vout OVP OPP . NCP1251 1 6 2 5 3 4 ramp comp. Figure 1. Typical Application Example Pin N Pin Name Function Pin Description 1 GND The controller ground. 2 FB Feedback pin Hooking an optocoupler collector to this pin will allow regulation. 3 OPP/OVP Adjust the Over Power Protection A resistive divider from the auxiliary winding to this pin sets the OPP Latches off the part compensation level. When brought above 3 V, the part is fully latched off. 4 CS Current sense + ramp This pin monitors the primary peak current but also offers a means to compensation introduce ramp compensation. 5 V Supplies the controller This pin is connected to an external auxiliary voltage and supplies the CC controller. When the V exceeds a certain level, the part permanently CC latches off. 6 DRV Driver output The drivers output to an external MOSFET gate. OPTIONS Controller Frequency OCP V OVP OVP/OTP CC NCP1251ASN65T1G 65 kHz Latched Latched Latched NCP1251BSN65T1G 65 kHz Autorecovery Latched Latched NCP1251CSN65T1G 65 kHz Autorecovery Autorecovery Latched NCP1251FSN65T1G 65 kHz Autorecovery Latched Latched NCP1251ASN100T1G 100 kHz Latched Latched Latched NCP1251BSN100T1G 100 kHz Autorecovery Latched Latched NOTE: F version has a different foldback scheme for improved efficiency. ORDERING INFORMATION Package V OVP Switching CC Device Marking OCP Protection Protection Frequency Package Shipping NCP1251ASN65T1G 5AA Latch Latch 65 kHz NCP1251BSN65T1G 5A2 Autorecovery Latch 65 kHz NCP1251CSN65T1G 5AE Autorecovery Autorecovery 65 kHz TSOP6 3000 / (PbFree) Tape & Reel NCP1251FSN65T1G 5AF Autorecovery Latch 65 kHz NCP1251ASN100T1G 5AC Latch Latch 100 kHz NCP1251BSN100T1G 5AD Autorecovery Latch 100 kHz For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. www.onsemi.com 2