The NCP101X series integrates a fixed frequency current mode controller and a 700V MOSFET from providing monolithic switcher low standby power offline switching power supplies. Housed in a PDIP-7 PDIP-7 gull-wing, or SOT-223 package, the NCP101X provides everything needed to build a rugged, low-cost power supply, including soft-start, frequency jitter, short-circuit protection, cycle skip, and maximum peak Current set point and dynamic self-powering (no need for auxiliary winding). Unlike other monolithic solutions, the NCP101X is naturally quiet: operating at rated load, the part switches at one of the available frequencies (65 - 100 - 130 kHz). When the current setpoint drops below a given value, eg the demand for output power diminishes, the IC automatically enters a so-called skip cycle mode and provides excellent light-load efficiency. Since this usually occurs at 1/4 of the maximum peak, no noise occurs. Therefore, the standby power is reduced to the lowest noiseless generation. Short circuit detection occurs when the feedback signal disappears, for example in a true short circuit condition or in the case of a broken optocoupler. External disable or simply pull feedback is easy to do to pin down or latch it off via an inexpensive ground thyristor complete latch. Finally, soft-start and frequency jitter further simplify the design task and rapidly develop low-cost, powerful offline power supplies. To improve standby performance, an auxiliary connected winding stops DSS operation and helps consume less than 100 mW of high wire. In this mode, built-in overvoltage lockout protection prevents the optocoupler from applying the brakes from a fatal runaway under high voltage conditions. These devices are available in economical 8-pin dual in-line and 4-pin SOT-223 packages.

Features • Built-in 700 V MOSFET with on-resistance of 11 typical? and 22?
• Large creepage distance pins at high voltage • Current mode fixed frequency operation: 65 kHz - 100 kHz - 130 kHz • Skip cycle operation at low peak current only: no noise!
• Dynamic self-powered, no need for auxiliary winding • Internal 1.0 ms soft-start • Latching overvoltage protection with auxiliary winding operation • Better EMI frequency jitter signature Power supply if auxiliary winding is used • Internal temperature shutdown • Directly connected optocoupler • SPICE model available for analysis of transients • Lead-free package available*

Typical applications • Charger for low power AC/DC adapter • Auxiliary power supply (USB interface, appliances, TV, etc.)