The NCP1377 combines a true current mode modulator and a demagnetization detector which ensures full borderline/critical Conduction Mode in any load/line conditions together with minimum drain voltage switching (Quasi−Resonant operation). Due to its inherent skip cycle capability, the controller enters burst mode as soon as the power demand falls below a predetermined level. As this happens at low peak current, no audible noise can be heard. For NCP1377, an internal 8.0 s timer prevents the free−run frequency to exceed 100 kHz (therefore below the 150 kHz CISPR−22 EMI starting limit), while the skip adjustment capability lets the user select the frequency at which the burst foldback takes place. For NC1377B, the internal timer duration is reduced to 3.0 s to allow operation at higher frequencies (up to 300 kHz).

Features • Free−Running Borderline/Critical Mode Quasi−Resonant Operation
• Latched Overvoltage Protection
• Auto−Recovery Short−Circuit Protection Via UVLO Crossover
• External Latch Triggering, e.g. Via Overtemperature Signal
• Current−Mode with Adjustable Skip Cycle Capability
• Internal 1.0 ms Soft−Start
• Internal Temperature Shutdown
• Internal Leading Edge Blanking
• 500 mA Peak Current Source/Sink Capability
• Under Voltage Lockout Level of 12.5 V (On) and 7.5 V (Min)
• Direct Optocoupler Connection
• SPICE Models Available for TRANsient Analysis
• Internal Minimum TOFF
• Pb−Free Packages are Available

Typical Applications • AC−DC Adapters for Notebooks, etc.
• Offline Battery Chargers
• Consumer Electronics (DVD Players, Set−Top Boxes, TVs, etc.)
• Auxiliary Power Supplies (USB, Appliances, TVs, etc.)

Manufacturer	onsemi
Product Category	AC DC Converters, Offline Switchers
Series	NCP1377
Packaging	Tube
Unit-Weight	0.030018 oz
Mounting-Style	Through Hole
Package-Case	8-DIP (0.300", 7.62mm), 7 Leads
Operating-Temperature	-40°C ~ 125°C (TJ)
Mounting-Type	Through Hole
Supplier-Device-Package	7-PDIP
Watt	-
Number-of-Outputs	1 Output
Output-Isolation	Isolated
Internal-Switch-s	No
Voltage-Breakdown	-
Topology	Flyback
Voltage-Start-Up	12.5V
Voltage-Supply-Vcc-Vdd	7.5 V ~ 18 V
Duty-Cycle	-
Frequency-Switching	Up to 100kHz
Fault-Protection	Current Limiting, Over Temperature, Over Voltage
Control-Features	-
Maximum Operating Temperature	+ 150 C
Output-Voltage	18 V
Output-Current	500 mA
Switching-Frequency	100 kHz
Fall-Time	20 ns
Rise-Time	40 ns
Package-Case	PDIP-7