NCP1338 PWM Current-ModeController for Free RunningQuasi-Resonant Operation
The NCP1338 combines a true current mode
modulator and ademagnetization detector which ensures full Borderline/CriticalConduction Mode in any load/line conditions together withminimum drain voltage switching (Quasi-Resonant operation). The
transformer core reset detection is done internally, without using anyexternal signal, due to the Soxyless concept. The frequency isinternally limited to 130 kHz, preventing the controller from
operating above the 150 kHz CISPR-22 EMI starting limit.By monitoring the feedback pin activity, the controller entersripple mode as soon as the power demand falls below apredetermined level. As each restart is softened by an internalSoft-Skip
http://onsemi.com MARKINGDIAGRAM , and as the frequency cannot go below 25 kHz, noaudible noise can be heard.The NCP1338 also features an efficient protective circuitry which,in presence of an overcurrent condition, disables the output pulses
and enters a safe burst mode, trying to restart. Once the default hasgone, the device auto-recovers. Also included is a bulk voltagemonitoring function (known as brown-out protection), an adjustable
overpower compensation, and a V
PDIP-7P SUFFIXCASE 626B NCP1338PAWLYYWWG1 SOIC-7D SUFFIXCASE 751U P1338ALYW 187
(Note: Microdot may be in either location) CC OVP. Finally, an internal 4.0 msSoft-Skip eliminates the traditional startup stress. NCP1338 can beused in applications where the V
A= Assembly LocationWL, L= Wafer LotYY, Y= YearWW, W= Work WeekG, CC supply voltage is delivered by anexternal dc voltage source.
= Pb-Free Package
(Top View)FBBOCSGNDDRVHVVCC Features
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Free-Running Borderline/Critical Mode Quasi-Resonant Operation
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Current-Mode
PIN CONNECTIONS
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Soft-Skip Mode with Minimum Switching Frequency for Standby
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Auto-Recovery Short-Circuit Protection Independent of AuxiliaryVoltage
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Overvoltage Protection
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Brown-Out Protection
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Two Externally Triggerable Fault Comparators (one for a disablefunction, and the other for a permanent latch)
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Internal 4.0 ms Soft-Skip
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500 mA Peak Current Drive Sink Capability
ORDERING INFORMATION
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130 kHz Max Frequency
DevicePackageShipping †
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Internal Leading Edge Blanking
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Internal Temperature Shutdown
NCP1338PGPDIP-7(Pb-Free)50 Units/Rail
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Direct Optocoupler Connection
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Dynamic Self-Supply with Levels of 12 V (On) and 10 V (Off)
NCP1338DR2GSOIC-7(Pb-Free)2500 Tape & Reel
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SPICE Models Available for TRANsient and AC Analysis
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These are Pb-Free Devices
†For information on tape and reel specifications,including part orientation and tape sizes, pleaserefer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
1234865 Typical Applications
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Ac-dc Adapters for Notebooks, etc.
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Offline Battery Chargers
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Consumer Electronics (DVD Players, Set-Top Boxes, TVs, etc.)
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Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
 Semiconductor Components Industries, LLC, 2008 Publication Order Number: April, 2008 - Rev. 01 NCP1338/D
